Method and apparatus for designing broadcast channel for nr in wireless communication system

ABSTRACT

According to the present invention, a common control signal via a group common control channel (GCCC) for a new radio access technology (NR) is defined. A user equipment (UE) receives the common control signal from a network via GCCC. The common control signal is for all UEs or a group of UEs in a cell. The UE handles the priority of the common control signal compared to other signals. For example, the priority of the common control signal may be higher than a semi-static UE-specifically configured configuration, and may be lower than a cell—commonly or group-commonly configured configuration.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage filing under 35 U.S.C. 371 ofInternational Application No. PCT/KR2017/013616, filed on Nov. 27, 2017,which claims the benefit of U.S. Provisional Applications No. 62/426,326filed on Nov. 25, 2016, No. 62/452,392 filed on Jan. 31, 2017, No.62/454,616 filed on Feb. 3, 2017, No. 62/473,451 filed on Mar. 19, 2017,No. 62/476,620 filed on Mar. 24, 2017, No. 62/565,068 filed on Sep. 28,2017, and No. 62/434,388 filed on Dec. 14, 2016, the contents of whichare all hereby incorporated by reference herein in their entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to wireless communications, and moreparticularly, to a method and apparatus for designing a broadcastchannel, e.g. group common or cell common, for a new radio accesstechnology (NR) in a wireless communication system.

Related Art

3rd generation partnership project (3GPP) long-term evolution (LTE) is atechnology for enabling high-speed packet communications. Many schemeshave been proposed for the LTE objective including those that aim toreduce user and provider costs, improve service quality, and expand andimprove coverage and system capacity. The 3GPP LTE requires reduced costper bit, increased service availability, flexible use of a frequencyband, a simple structure, an open interface, and adequate powerconsumption of a terminal as an upper-level requirement.

As more and more communication devices require more communicationcapacity, there is a need for improved mobile broadband communicationover existing radio access technology. Also, massive machine typecommunications (MTC), which provides various services by connecting manydevices and objects, is one of the major issues to be considered in thenext generation communication. In addition, communication system designconsidering reliability/latency sensitive service/UE is being discussed.The introduction of next generation radio access technology consideringenhanced mobile broadband communication (eMBB), massive MTC (mMTC),ultra-reliable and low latency communication (URLLC) is discussed. Thisnew technology may be called new radio access technology (new RAT or NR)for convenience.

In NR, analog beamforming may be introduced. In case of millimeter wave(mmW), the wavelength is shortened so that a plurality of antennas canbe installed in the same area. For example, in the 30 GHz band, a totalof 100 antenna elements can be installed in a 2-dimension array of 0.5lambda (wavelength) intervals on a panel of 5 by 5 cm with a wavelengthof 1 cm. Therefore, in mmW, multiple antenna elements can be used toincrease the beamforming gain to increase the coverage or increase thethroughput.

In this case, if a transceiver unit (TXRU) is provided so thattransmission power and phase can be adjusted for each antenna element,independent beamforming is possible for each frequency resource.However, installing a TXRU on all 100 antenna elements has a problem interms of cost effectiveness. Therefore, a method of mapping a pluralityof antenna elements to one TXRU and adjusting the direction of a beamusing an analog phase shifter is considered. This analog beamformingmethod has a disadvantage that it cannot perform frequency selectivebeaming because it can make only one beam direction in all bands.

A hybrid beamforming with B TXRUs, which is an intermediate form ofdigital beamforming and analog beamforming, and fewer than Q antennaelements, can be considered. In this case, although there is adifference depending on the connection method of the B TXRU and Qantenna elements, the direction of the beam that can be simultaneouslytransmitted is limited to B or less.

For operating NR efficiently, various schemes have been discussed.Particularly, NR bands may be operated in unpaired spectrum to maximizebandwidth, and thus may be operated in a wideband. When downlink anduplink resources are multiplexed by time division multiplexing (TDM) inthe unpaired spectrum, to minimize UE power consumption, it is importantto indicate resource direction which may be dynamically changed.

SUMMARY OF THE INVENTION

The present invention relates to wireless communications, and moreparticularly, to a method and apparatus for designing a broadcastchannel, e.g. group common or cell common, for a new radio accesstechnology (NR) in a wireless communication system. The presentinvention discusses a common physical downlink control channel (PDCCH)design for NR. The group or cell common signaling may be used toindicate resource direction between downlink and uplink, and alsoindicate other information related to UE assumptions on measurements,transmission, and control/data monitoring.

In an aspect, a method for handling priority of a common control signalby a user equipment (UE) in a wireless communication system is provided.The method includes receiving the common control signal from a networkvia a group common control channel (GCCC), wherein the common controlsignal is for all UEs or a group of UEs in a cell, and handling thepriority of the common control signal compared to other signals.

In another aspect, a user equipment (UE) in a wireless communicationsystem is provided. The UE includes a memory, a transceiver, and aprocessor, operably coupled to the memory and the transceiver, thatcontrols the transceiver to receive the common control signal from anetwork via a group common control channel (GCCC), wherein the commoncontrol signal is for all UEs or a group of UEs in a cell, and handlesthe priority of the common control signal compared to other signals.

Group common or cell common broadcast channel for NR can be definedefficiently.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a 3GPP LTE system.

FIG. 2 shows structure of a radio frame of 3GPP LTE.

FIG. 3 shows a resource grid for one downlink slot.

FIG. 4 shows an example of subframe type for NR.

FIG. 5 shows an example of indicating which DL/UL pattern by commonsignal according to an embodiment of the present invention.

FIG. 6 shows an example of a procedure acquiring a beam index accordingto an embodiment of the present invention.

FIG. 7 shows an example of fallback operation according to an embodimentof the present invention.

FIG. 8 shows an example of subband formation according to an embodimentof the present invention.

FIG. 9 shows an example of CSS formation according to an embodiment ofthe present invention.

FIG. 10 shows an example of utilizing a guard band for common signalaccording to an embodiment of the present invention.

FIG. 11 shows an example of patterns for coexistence of LTE and NRaccording to an embodiment of the present invention.

FIG. 12 shows a method for handling priority of a common control signalby a UE according to an embodiment of the present invention.

FIG. 13 shows a wireless communication system to implement an embodimentof the present invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 shows a 3GPP LTE system. The 3rd generation partnership project(3GPP) long-term evolution (LTE) system 10 includes at least one eNodeB(eNB) 11. Respective eNBs 11 provide a communication service toparticular geographical areas 15 a, 15 b, and 15 c (which are generallycalled cells). Each cell may be divided into a plurality of areas (whichare called sectors). A user equipment (UE) 12 may be fixed or mobile andmay be referred to by other names such as mobile station (MS), mobileterminal (MT), user terminal (UT), subscriber station (SS), wirelessdevice, personal digital assistant (PDA), wireless modem, handhelddevice. The eNB 11 generally refers to a fixed station that communicateswith the UE 12 and may be called by other names such as base station(BS), base transceiver system (BTS), access point (AP), etc.

In general, a UE belongs to one cell, and the cell to which a UE belongsis called a serving cell. An eNB providing a communication service tothe serving cell is called a serving eNB. The wireless communicationsystem is a cellular system, so a different cell adjacent to the servingcell exists. The different cell adjacent to the serving cell is called aneighbor cell. An eNB providing a communication service to the neighborcell is called a neighbor eNB. The serving cell and the neighbor cellare relatively determined based on a UE.

This technique can be used for DL or UL. In general, DL refers tocommunication from the eNB 11 to the UE 12, and UL refers tocommunication from the UE 12 to the eNB 11. In DL, a transmitter may bepart of the eNB 11 and a receiver may be part of the UE 12. In UL, atransmitter may be part of the UE 12 and a receiver may be part of theeNB 11.

The wireless communication system may be any one of a multiple-inputmultiple-output (MIMO) system, a multiple-input single-output (MISO)system, a single-input single-output (SISO) system, and a single-inputmultiple-output (SIMO) system. The MIMO system uses a plurality oftransmission antennas and a plurality of reception antennas. The MISOsystem uses a plurality of transmission antennas and a single receptionantenna. The SISO system uses a single transmission antenna and a singlereception antenna. The SIMO system uses a single transmission antennaand a plurality of reception antennas. Hereinafter, a transmissionantenna refers to a physical or logical antenna used for transmitting asignal or a stream, and a reception antenna refers to a physical orlogical antenna used for receiving a signal or a stream.

FIG. 2 shows structure of a radio frame of 3GPP LTE. Referring to FIG.2, a radio frame includes 10 subframes. A subframe includes two slots intime domain. A time for transmitting one transport block by higher layerto physical layer (generally over one subframe) is defined as atransmission time interval (TTI). For example, one subframe may have alength of 1 ms, and one slot may have a length of 0.5 ms. One slotincludes a plurality of orthogonal frequency division multiplexing(OFDM) symbols in time domain. Since the 3GPP LTE uses the OFDMA in theDL, the OFDM symbol is for representing one symbol period. The OFDMsymbols may be called by other names depending on a multiple-accessscheme. For example, when SC-FDMA is in use as a UL multi-access scheme,the OFDM symbols may be called SC-FDMA symbols. A resource block (RB) isa resource allocation unit, and includes a plurality of contiguoussubcarriers in one slot. The structure of the radio frame is shown forexemplary purposes only. Thus, the number of subframes included in theradio frame or the number of slots included in the subframe or thenumber of OFDM symbols included in the slot may be modified in variousmanners.

The wireless communication system may be divided into a frequencydivision duplex (FDD) scheme and a time division duplex (TDD) scheme.According to the FDD scheme, UL transmission and DL transmission aremade at different frequency bands. According to the TDD scheme, ULtransmission and DL transmission are made during different periods oftime at the same frequency band. A channel response of the TDD scheme issubstantially reciprocal. This means that a DL channel response and a ULchannel response are almost the same in a given frequency band. Thus,the TDD-based wireless communication system is advantageous in that theDL channel response can be obtained from the UL channel response. In theTDD scheme, the entire frequency band is time-divided for UL and DLtransmissions, so a DL transmission by the eNB and a UL transmission bythe UE cannot be simultaneously performed. In a TDD system in which a ULtransmission and a DL transmission are discriminated in units ofsubframes, the UL transmission and the DL transmission are performed indifferent subframes. In a TDD system, to allow fast switching between DLand UL, UL and DL transmission may be performed within a samesubframe/slot in time division multiplexing (TDM)/frequency divisionmultiplexing (FDM) manner.

FIG. 3 shows a resource grid for one downlink slot. Referring to FIG. 3,a DL slot includes a plurality of OFDM symbols in time domain. It isdescribed herein that one DL slot includes 7 OFDM symbols, and one RBincludes 12 subcarriers in frequency domain as an example. However, thepresent invention is not limited thereto. Each element on the resourcegrid is referred to as a resource element (RE). One RB includes 12×7 or12×14 resource elements. The number N_(DL) of RBs included in the DLslot depends on a DL transmit bandwidth. The structure of a UL slot maybe same as that of the DL slot. The number of OFDM symbols and thenumber of subcarriers may vary depending on the length of a CP,frequency spacing, etc. For example, in case of a normal cyclic prefix(CP), the number of OFDM symbols is 7 or 14, and in case of an extendedCP, the number of OFDM symbols is 6 or 12. One of 128, 256, 512, 1024,1536, 2048, 4096 and 8192 may be selectively used as the number ofsubcarriers in one OFDM symbol.

5th generation mobile networks or 5th generation wireless systems,abbreviated 5G, are the proposed next telecommunications standardsbeyond the current 4G LTE/international mobile telecommunications(IMT)-dvanced standards. 5G includes both new radio access technology(new RAT or NR) and LTE evolution. Hereinafter, among 5G, NR will befocused. 5G planning aims at higher capacity than current 4G LTE,allowing a higher density of mobile broadband users, and supportingdevice-to-device, ultra-reliable, and massive machine communications. 5Gresearch and development also aims at lower latency than 4G equipmentand lower battery consumption, for better implementation of the Internetof things.

NR may use the OFDM transmission scheme or a similar transmissionscheme. NR may follow the existing LTE/LTE-A numerology, or may followthe different numerology from the existing LTE/LTE-A numerology. NR mayhave a larger system bandwidth (e.g. 100 MHz). Or, one cell may supportmultiple numerologies in NR. That is, UEs operating in differentnumerologies may coexist within one cell in NR.

It is expected that different frame structure may be necessary for NR.Particularly, different frame structure in which UL and DL may bepresent in every subframe or may change very frequently in the samecarrier may be necessary for NR. Different application may requiredifferent minimum size of DL or UL portions to support different latencyand coverage requirements. For example, massive machine-typecommunication (mMTC) for high coverage case may require relatively longDL and UL portion so that one transmission can be successfullytransmitted. Furthermore, due to different requirement onsynchronization and tracking accuracy requirements, different subcarrierspacing and/or different CP length may be considered. In this sense, itis necessary to consider mechanisms to allow different frame structurescoexisting in the same carrier and be operated by the same cell/eNB.

In NR, utilizing a subframe in which downlink and uplink are containedmay be considered. This scheme may be applied for paired spectrum andunpaired spectrum. The paired spectrum means that one carrier consistsof two carriers. For example, in the paired spectrum, the one carriermay include a DL carrier and an UL carrier, which are paired with eachother. In the paired spectrum, communication, such as DL, UL,device-to-device communication, and/or relay communication, may beperformed by utilizing the paired spectrum. The unpaired spectrum meansthat that one carrier consists of only one carrier, like the current 4GLTE. In the unpaired spectrum, communication, such as DL, UL,device-to-device communication, and/or relay communication, may beperformed in the unpaired spectrum.

Further, in NR, the following subframe types may be considered tosupport the paired spectrum and the unpaired spectrum mentioned above.

(1) Subframes including DL control and DL data

(2) Subframes including DL control, DL data, and UL control

(3) Subframes including DL control and UL data

(4) Subframes including DL control, UL data, and UL control

(5) Subframes including access signals or random access signals or otherpurposes.

(6) Subframes including both DL/UL and all UL signals.

However, the subframe types listed above are only exemplary, and othersubframe types may also be considered.

FIG. 4 shows an example of subframe type for NR. The subframe shown inFIG. 4 may be used in TDD system of NR, in order to minimize latency ofdata transmission. Referring to FIG. 4, the subframe contains 14 symbolsin one TTI, like the current subframe. However, the subframe includes DLcontrol channel in the first symbol, and UL control channel in the lastsymbol. A region for DL control channel indicates a transmission area ofa physical downlink control channel (PDCCH) for Downlink controlinformation (DCI) transmission, and a region for UL control channelindicates a transmission area of a physical uplink control channel(PUCCH) for uplink control information (UCI) transmission. Here, thecontrol information transmitted by the eNB to the UE through the DCI mayinclude information on the cell configuration that the UE should know,DL specific information such as DL scheduling, and UL specificinformation such as UL grant. Also, the control information transmittedby the UE to the eNB through the UCI may include a hybrid automaticrepeat request (HARQ) acknowledgement/non-acknowledgement (ACK/NACK)report for the DL data, a channel state information (CSI) report on theDL channel status, and a scheduling request (SR). The remaining symbolsmay be used for DL data transmission (e.g. physical downlink sharedchannel (PDSCH)) or for UL data transmission (e.g. physical uplinkshared channel (PUSCH)).

According to this subframe structure, DL transmission and ULtransmission may sequentially proceed in one subframe. Accordingly, DLdata may be transmitted in the subframe, and ULacknowledgement/non-acknowledgement (ACK/NACK) may also be received inthe subframe. In this manner, the subframe shown in FIG. 4 may bereferred to as self-contained subframe. As a result, it may take lesstime to retransmit data when a data transmission error occurs, therebyminimizing the latency of final data transmission. In the self-containedsubframe structure, a time gap may be required for the transitionprocess from the transmission mode to the reception mode or from thereception mode to the transmission mode. For this purpose, some OFDMsymbols at the time of switching from DL to UL in the subframe structuremay be set to the guard period (GP).

Hereinafter, various aspects of designing a broadcast channel, e.g.group common or cell common, for NR are described according toembodiments of the present invention. In NR, single beam operationand/or multi beam operation may be expected. Furthermore, due todifferent bandwidth between different UEs, different data subband may beconfigured to different UEs. Also, different network entity withdifferent transmission/reception points (TRPs) may transmit differentinformation.

The present invention discusses efficient mechanism to indicate commonsignal (or, common information) to all UEs or a group of UEs in a cell.The group of UEs may be grouped based on e.g. one of the followings.

-   -   Data subband (or, bandwidth part (BWP)): UEs sharing the same        data subband may be grouped together.    -   Primary TRP in charge: UEs may be grouped together based on the        primary TRP which takes care of UEs.

Other reasons of UE grouping is not prohibited. For example, the networkmay separate UEs into different groups based on usage scenario (e.g.ultra-reliable and low latency communication (URLLC)/enhanced mobilebroadband communication (eMBB)), UE capability (e.g. support NR/LTEcoexistence or not), or numerology used for data transmission (e.g. 15kHz or 30 kHz subcarrier spacing), etc. Particularly, when a UE supportsmultiple numerologies by TDM, numerology of group common signaling mayalso be different. And for that, numerology used in group commonsignaling may be configured/determined for each group. Further, subframemay be used interchangeably with slot in the present invention.

According to an embodiment of the present invention, contents of commonsignal is proposed. Contents of common signal may include at least oneof the following information.

-   -   Whether a type of the current subframe is UL-centric or        DL-centric or UL or DL or reserved    -   Whether a type of the next subframe type is UL-centric or        DL-centric or UL or DL or reserved    -   Whether a type of a few next subframe including the current        subframe types are UL-centric or DL-centric or UL or DL or        reserved    -   Whether a type of a few next subframe types are UL-centric or        DL-centric or UL or DL or reserved    -   Whether the current subframe is scheduled with single-level DCI        or two/multi-level DCI    -   Whether the next subframe is scheduled with single-level DCI or        two/multi-level DCI    -   The size of common or group-specific shared control resource set    -   The set of OFDM symbols or the set of search spaces or the set        of candidates: The targeted UEs may be expected to monitor the        set of OFDM symbols/search spaces/candidates at the current or        next subframe    -   The set of OFDM symbols and/or frequency regions: The targeted        UEs may not be expected to monitor or use for control/data        mapping the set of OFDM symbols/frequency regions. For example,        forward compatibility resource or resource not usable for NR due        to LTE/NR coexistence, etc., may be indicated.    -   Reserved resource for different numerology UEs: This may be        included in the above, or separate indication may also be        possible.    -   Reserved resource for sidelink or backhaul: This may be included        in the above or separate indication may also be possible. More        importantly, sidelink or backhaul link resource may be        represented as ‘reserved’ or ‘unknown’ resource to regular        access link UEs, as the resources are not usable for such UEs.    -   Reserved resource for forward/backward compatible reasons, e.g.        for LTE use in case of LTE-NR UL and/or DL sharing: Particularly        UL, if a UE is connected to both LTE and NR in the same UL        spectrum, time division multiplexing (TDM) on UL sharing may be        considered, and resources allocated to the LTE UL transmission        may be configured as reserved resource in perspective of NR UL.    -   Indication of actual DL resource, UL resource and/or reserved        resource: DL, UL and reserved resource may be indicated        separately. For paired spectrum, reserved resource may be        configured for DL and UL spectrum, separately. Further, there        may be semi-statically configured reserved resource in frequency        and/or time domain. Reserved resource may be called different        names. For example, reserved resource may be called flexible        resource, which means resource used for DL or UL flexibly. Or,        reserved resource may be called unknown resource, which means        resource of which the usage is not known until determined. When        the signal is not available, all the resources may be unknown        resources or flexible resources, which may be changed to        different resource type.

For example, DL resource may have one of the following patterns.

-   -   All DL slot    -   Slot length—2 DL length    -   Slot length—3 DL length    -   Slot length—4 DL length    -   Only control region DL length.    -   Alternatively, other numbers may also be considered.

For UL resource, one of the following patterns may be considered.

-   -   All UL slot    -   Slot length—1-control region size UL length    -   Slot length—2-control region size UL length    -   Slot length—3-control region size UL length    -   Configured UCI region size UL length (e.g. 1 or 2 or 3 or X        depending on configuration).    -   Alternatively, other numbers may also be considered.

For reserved resource, one of the following patterns may be considered.

-   -   First X symbols: X may be higher layer configured.    -   Bitmap pattern 1: For example, bitmap pattern 1 may be [0 0 0 0        1 1 1] in which reserved bits are reserved for the latter slot        portion.    -   Bitmap pattern 2: For example, bitmap pattern 2 may be [1 1 1 1        0 0 0] in which reserved bits are reserved for the first slot        portion.    -   The configuration of bitmap patterns may be semi-statically        configured, and indices may be indicated via dynamic signaling.    -   No reserved portion    -   The entire slot is reserved    -   In combination of DL, UL and reserved resource, the slot type        may be defined as ‘DL(s)-Unknown(s)-UL(s)’ for each slot. Each        DL or Unknown or UL may have 0, 1, 2 . . . 14 symbols in each        slot, but total number of symbols in each slot may be restricted        as 14. When multiple DL-UL switching occurs, ‘DL-Unknown-UL’        pattern may be applied to 7 OFDM symbols instead of 14 OS or 4/3        symbols within 7 OFDM symbols case (for 2, 4 switching,        respectively). In other words, slot type or sub-slot type may        start with zero or more DL symbols and end with zero or more UL        symbols. And, undefined symbols may be treated as unknown        resources or reserved resources.    -   A set of beam pairs or transmission beams used in the next few        slots: To minimize UE blind detection overhead, a sequence of        transmission beam in a slot or over a next few slots may be        indicated. This information may be transmitted per each beam.        This information may be transmitted in slot in which control        channels are transmitted via beam sweeping of multiple beams,        regardless of actual scheduling or common data scheduling. In        other words, the information may be transmitted along with        common data.

The proposals in the present invention may also be applied to the casewhen a UE acquires slot formation via semi-static signaling. Thesemi-static signaling may be indicated cell-specifically,UE-group-common or UE-specifically. Particularly, reserved resource maybe configured semi-statically, and dynamic indication may not carryexplicit indication on the reserved resource. In case of semi-staticconfiguration, the patterns of slot formats may be used, and thebehavior of a UE may be similar as presented in the present invention.

A slot type may be indicated by a bitmap for each or a set of OFDMsymbols, and each bit may represent either DL or UL (or DL or UL orreserved resource). When DL/UL is used for type indication of each or aset of OFDM symbols, DL may include either DL or reserved resource.Alternatively, UL may include either UL or reserved resource. In otherwords, reserved resource may be expressed either DL or UL, if two typeindications are used. Moreover, the number of OFDM symbols belonging toeach set or each bit or the size of bitmap representing each slot may beconfigured by higher layer. The set of OFDM symbols corresponding to onebit in the bitmap may be 1 to slot size. When one slot type indicationis for a set of slots instead of one slot, a set of OFDM symbols withinthe set of slots may be defined. The number of slots indicated by oneslot type indication may also be configured by higher layer.

When multiple purposes of indication are achieved and one common signalmay be scheduled with a radio network temporary identity (RNTI), a UEmay search more than one RNTI to locate the necessary information. Eachcommon signal based on each RNTI may have different functionality. Forexample, for a URLLC UE, reserved resource for eMBB but not reserved forURLLC UE may be available for transmission/reception of URLLC traffic.Also, for example, UEs with triggered channel state informationreference signal (CSI-RS) may assume that the subframe/slot may transmitCSI-RS, whereas UEs with semi-static or persistent CSI-RS configurationmay assume that the subframe/slot may not transmit CSI-RS if thesubframe is indicated as UL-centric. Though, it is highly possible thatthe location of CSI-RS transmission may be different. Common signal maybe applicable to UEs with slot-based scheduling only or may also beapplicable to UEs with mini-slot based scheduling as well, depending onits configuration. When a UE is configured with mini-slot, it may beindicated whether common signal is also applicable to mini-slotscheduling or not. More generally, different RNTI or search space may beconfigured for mini-slot based scheduling to transmit common signal, ifdifferent group-common scheduling is applied. Depending on slot based ormini-slot based scheduling, a UE may apply different information fordifferent group-common control channel.

According to an embodiment of the present invention, combination ofdifferent information is proposed. Though one physical channel is used,different information set or information may be transmitted in eachincident depending on the configuration. For example, slot type,information of DL/UL/reserved resource may be indicated with differentperiodicity. For example, slot type may be transmitted with aperiodicity which is applied during the interval, and information ofDL/UL/reserved resource may be transmitted aperiodically or withdifferent periodicity which is applied only on the same slot. Dependingon the configuration, different content of common or group-commoncontrol channel may be expected. Also depending on its content, eventhough the channel itself is same (regarding channel coding, mapping,DCI format, etc.), the mapped candidate may be different. For example,slot type may be indicated in any candidate in the group common orcommon search space. However, if dynamic signaling on the number of OFDMsymbols is indicated, it may be mapped to the first or pre-fixed orsemi-statically configured candidate index so that it can be obtainedwithout any blind decoding (to minimize latency).

According to an embodiment of the present invention, signal transmissionperiodicity in time is proposed. The following mechanisms may beconsidered for indication of common signal. In the below description,the common signal refers a group or cell-specific signal which areapplicable to all UEs or a group of UEs in a cell, depending on how thesignal is designed. If multiple common signals are used for differentpurposes or different UEs, one or more of the following mechanisms maybe jointly used.

(1) The indication may be done at the current subframe

The indication may have higher priority than semi-statically configuredsignals, such as semi-static configuration of sounding reference signal(SRS) transmission.

The indication may have lower priority than dynamically indicatedscheduling. The UE may ignore common signal if the scheduling saysotherwise. In the dynamic indication has been transmitted “x”slots/subframes before, common signal may have higher priority thandynamically indicated scheduling. In other words, dynamically indicatedscheduling occurred in the same subframe/slot may have higher prioritythan common signal. Otherwise, common signal may have higher prioritythan the dynamically indicated scheduling. In other words, the mostrecent signaling may always have the highest priority than othersignaling, regardless of common/UE-specific and/or dynamic/semi-staticsignaling. Alternatively, as common signal may not be received by UE,the UE-specific dynamic signaling may always have higher priority thancommon signal.

If the indication is not given, a UE may always assume that commonsignal is present. Thus, if common signal is not present, the currentsubframe/slot may not be valid or the resource type(s) within a slot maynot be determined. Alternatively, a UE may opportunistically assume thatcommon signal may be present. If common signal is not present, thedefault configuration or previous subframe/slot's configuration mayapplied in the subframe/slot. Default configuration may be given per UEor UE-group or per cell. Alternatively, a UE may not be required to readcommon signal. That is, it may be a UE capability to read common signal.If a UE does not have capability to read common signal, fallbackbehavior for a UE may be used. Alternatively, a UE may assume differentvalue for each field or each indication to avoid any negative impact onthe network side.

If common signal is supposed to be present in every subframe, and commonsignal is not detected at the first OFDM symbol of a slot, the UE maysearch common signal in the next OFDM symbol. The UE may assume that thefirst OFDM symbol is blank OFDM symbol if common signal is not detected.More generally, this common signal may be transmitted in every symbol toindicate whether the current symbol is valid or invalid.

(2) The indication may be done before the subframe

For example, to indicate whether the first OFDM symbol is blank/reservedor not, indication before the current slot/subframe may also beconsidered. Furthermore, to minimize latency, common signal may betransmitted before the current slot/subframe. Also, to adapt the networkbandwidth, bandwidth may also be indicated before the actualtransmission. Also, if the network wants to dynamically reconfigure orchange the frequency region in which common signal is transmitted,common signal may be transmitted before. Common signal may indicate thefollowing subframe/slot, and multiple indication may be possible.

In terms of priority, similar priority described above may be applied tothis case as well.

(3) The indication may be done at the end of current subframe or at thebeginning of next subframe

For example, the indication cannot be transmitted before or some changesmay occur during the slot/subframe. In this case, the indication fromthe next or at the end of current subframe may also be considered. Theend of slot/subframe may refer the last OFDM symbol(s) of theslot/subframe or the last OFDM symbol(s) of the DwPTS (DL portion)excluding guard period and/or UL portion. The signal for this mayinclude backward indication of reserved signal or punctured resource. Ifcommon signal is transmitted at the end of slot/subframe, data ratematching may be needed. One of the following options may be consideredfor data rate matching.

-   -   Data rate matching may always be performed on the common or        group common control channel.    -   Data rate matching may be performed only on the resource used by        the detected common or group common control channel(s).    -   Data rate matching may not be performed and common or group        common control may perform puncturing.    -   One options among different option may be configured by the        network.    -   Common signal may be transmitted within the reserved resource or        guard period so that data rate matching is not subject to the        transmission of common or group common control channel. The        similar approach may be considered for the case that common or        group common control channel is transmitted in a fixed        time/frequency location within a slot (e.g. fixed by search        space candidate, fixed by frequency resource or fixed by        time/frequency resource, etc.), and control channels may be        transmitted cross the common or group common control channel        resource. In such case, data rate matching on control channel        may be done by similar approach as mentioned above.

(4) The indication may be done simultaneously at the current and nextsubframe

Depending on indication type, indication to either current or nextslot/subframe or both current/next subframe may also be considered. Thismay be effective when the first OFDM symbol of next subframe/slot may bereserved or resource in which common signal is transmitted is reserved.

(5) The indication may be done simultaneously at the current subframeand/or future

Similar to the above option, but the indication may be dynamicallychanged to indicate only current subframe, or only next subframes orboth. To differentiate, one field may be present to indicate whichindication is used in common signal.

(6) The indication may be done periodically. Particularly with (4)/(5),different number of slots/subframes may be indicated per eachindication.

In this case, discontinuous reception (DRX) UEs in On_Duration may notbe expected to receive common control channels, or may not be expectedto change or apply certain behaviors based on the common signal. Inother words, operation without reading the common or group commoncontrol channel may be performed particularly for DRX UEs.

(7) The indication may be done via media access control (MAC) controlelement (CE) activation/deactivation.

(8) The indication may be done periodically/aperiodically for multiplesubframes/slots

In this case, the indication may also include the duration for whichindication is applied. Or, the indication may have a bitmap field toindicate which next subframes are applied with the indicatedinformation.

(9) Similar to enhanced interference management and traffic adaptation(eIMTA) DCI, within certain interval (which may be configured by higherlayer), one or multiple times of common or group common control channelsmay be transmitted. If multiple times of transmission occur within oneperiod/interval, the same information may be carried. This is to enhancethe reliability and also to handle DRX UEs. More particularly, if commonsignal is configured to be transmitted periodically, considering thatthe resources may not be available due to reserved/UL, duration/windowwithin each period where a UE can monitor multiple occasions of controltransmission may be configured to increase the opportunities of commonsignal transmission.

According to an embodiment of the present invention, handling differentinformation between semi-static configuration and a common PDCCH orbetween dynamic scheduling DCI and a common DCI is proposed. CommonPDCCH may be called another name, e.g. common or group control channel(GCCC). Depending on the content, different handling seems necessary ifthe GCCC indicates different information from the known information bysemi-static configuration or by dynamic scheduling. For example, if aslot type includes guard/reserved period which can be used for certainapplications such as URLLC, URLLC UEs need to assume that reservedportions may be used for URLLC based on dynamic scheduling. Anotherissue is how to handle grant-free resource whether this may betransmitted in DL/reserved resource indicated by the GCCC or not.Generally, when the network indicates DL resource for the grant-freeresource portion, grant-free transmission may not be successfullyreceived by the network regardless whether the UE transmits or not. Inthis sense, it is generally better to assume that grant-free resourcemay be cancelled by the GCCC. However, URLLC UEs can still utilize thereserved resource. To address this issue, separate slot type indicationmay be given to different UEs (e.g. eMBB UEs and URLLC UEs). Or, a UEmay assume that semi-statically configured UL resources are valid unlessthe portions are reclaimed as DL. If preemption indication is used, aGCCC may override the scheduling DCI.

However, to support very reliable/low latency URLLC UEs, some grant-freeresources may be reserved and cannot be cancelled by any common signalor dynamic signaling, unless reconfiguration is done. UEs granted toutilize such resource may ignore GCCC signal for grant-free resourcedetermination.

In terms of overall priority, the following options may be considered.Semi-static configuration in flexible resource may or may not be changedby GCCC. The flexible resource may be determined by the resource whichis not indicated as fixed DL resource or fixed UL resource bysemi-static DL/UL assignment, which may be transmitted in remainingsystem information (RMSI)/on-demand system information (OSI) and/orUE-specific signaling. DL/UL assignment may be given to a SCell viaUE-specific signaling. In UE-specific signaling, different DL/ULassignment may be possible. Cell-common DL/UL assignment may betransmitted via cell-specific signaling such as RMSI/OSI, andUE-specific may be transmitted via UE-specific signaling. As there maybe different behavior depending on the characteristic of DL/ULassignment, the type needs to be separated at SCell configuration. Itmay also be differentiated whether it is included in SIB or not.

(1) GCCC may have the lowest priority. Unless there is no conflict, a UEmay apply the configuration indicated by the GCCC.

(2) GCCC may have the highest priority. For the configured RNTI to readGCCC, the information may have higher priority compared to other dynamicDCI or semi-static configuration.

(3) GCCC may have the higher priority than the UE-specificallyconfigured configuration, may have the lower priority than thecell-commonly configured configurations or group-commonly configuredconfigurations, and may have the lower priority than the UE-specificallydynamically configured configurations. In terms of dynamic DCI, thepriority may also be determined based on effective timing. If commonsignal is applied or transmitted after the dynamic DCI, common signalmay have higher priority than the dynamic DCI. For example, if dynamicDCI schedules cross-subframe/slot scheduling at k-slots afterwards wherecommon signal is transmitted between n and n+k slots, common signal mayhave higher priority than the dynamic DCI. Or, to minimize ambiguity oruncertainty about whether a UE has received the common signal or not,the dynamic DCI may have the higher priority than GCCC regardless oftiming.

More generally, the following options may be considered for thecollision case between GCCC and semi-statically configured resources,particularly in perspective of slot indication. When no collision occurs(i.e. information carried in GCCC and semi-static configuration does notconflict), information in each is obeyed.

(1) Option 1: GCCC may always override semi-static resource includingphysical broadcast channel (PBCH)/primary synchronization signal(PSS)/secondary synchronization signal (SSS) resources. Even thoughPBCH/PSS/SSS resources are semi-statically or predefined, it may bechanged by GCCC. When a UE detects GCCC which indicates OFDM symbols forPBCH/PSS/SSS are DL, resources for PBCH/PSS/SSS may be reserved forPBCH/PSS/SSS so that data may be rate matched around those reservedresources. If GCCC indicates UL, a UE may assume that resources forPBCH/PSS/SSS may not be used for PBCH/PSS/SSS and may be preempted by ULtransmission.

(2) Option 2: GCCC may override most semi-static resources withexceptions. Exceptions may include one or more PBCH/PSS/SSS/controlregion/grant-free resources.

(3) Option 3: GCCC cannot override semi-static resource, at leastconfigured cell-specifically or group-specifically. In other words,configuration by system information block (SIB)/PBCH may not bechangeable, whereas UE-specific configurations (e.g. CSI-RS) may bechanged or overridden by GCCC. In other words, GCCC cannot overrideconfiguration by RMSI/OSI, whereas it may override any configurationgiven by UE-specific configuration. In terms of SCell, configuration ofSIB may be considered as UE-specific signaling as well. Or, inUE-specific configuration, at least for SCell SIB configuration, it maybe indicated whether the configuration can be overridden or not or itmay be determined whether the configuration is included in SIB or not.

(4) Option 4: GCCC cannot override semi-static resource includingUE-specific configuration. Another alternative is to put higher priorityon semi-static configuration.

(5) Option 5: Priority may be configured. Either for each configurationor general priority between semi-static configuration and dynamic PDCCHmay be configured by higher layer along with GCCC enablingconfiguration. When priority is configured per each configuration, itmay be explicitly indicated in each configuration (e.g. theconfiguration cannot be overridden by GCCC or can be overridden byGCCC). As a default, resources predefined in the specification, unlessotherwise configured by higher layer later, may not be overridden byGCCC and semi-static configuration may be overridden by GCCC.

(6) Option 6: GCCC may always override semi-static configuration. Inother words, GCCC may higher priority than semi-static configuration.

(7) Option 7: GCCC may override semi-static configuration in resourcesconsidered as flexible and cannot override semi-static configurations inresources considered as fixed DL or UL resources. The flexible resourcemay be determined by semi-static DL/UL configuration. If the semi-staticDL/UL configuration is given by cell-specific configuration and/orUE-specific configuration and/or UE-group common configuration, theindicated fixed DL/UL resources may be considered as fixed DL or UL.Alternatively, the flexible resource may be determined by resources orRS types of semi-static configuration. For certain RS (e.g. tracking RS,beam management CSI-RS or SS block or physical random access channel(PRACH)), configuration may define fixed DL or fixed UL resources, andothers may be considered as flexible resources. Alternatively, theflexible resource may be determined by configuration method. Forexample, resources which are configured semi-statically by broadcastmessages such as RMSI or configured cell-specially may be considered asfixed DL or UL resources. For example, if beam management RS is definedby RMSI, or SS block or PRACH is defined by RMSI, the configuredresources may be considered as fixed DL or UL resources.

If semi-static DL/UL configurations are given, and there are multipleconfigurations with different RS type and/or based on differentconfiguration methods (i.e. multiple approaches described above are usedjointly), it may be assumed that union of fixed DL/UL resources is usedby semi-static DL/UL configuration and semi-static RS configuration, orit may be assumed that conflict does not occur. If conflict occurs,either the UE may treats the case as an error case, or the UE may followsemi-static DL/UL configuration.

For different options described above, it may need to be clarified thatresources reserved for PBCH/PSS/SSS may include only actual resourcesintended for PBCH/PSS/SSS. For example, potential resources forPBCH/PSS/SSS may be reserved for N SS block and only a subset of N SSblocks may be used. In this case, unused SS blocks may be indicated toUEs so that it can be used for control/data/other transmission. Asunused resources are unused somewhat in a deterministic manner, theunused resources may be indicated by higher layer (group-common orcell-specific or UE-specific) to UEs. In such a case, even with option2, resource diction on such unused resource may be changed (i.e. unusedresources may not be accounted for PBCH/PSS/SSS region).

Different priority between semi-static configuration and GCCC may bedefined (e.g. default behavior or priority rule). For example, GCCC mayoverride CSI-RS configuration, but GCCC cannot override grant freeresources (at least some resources).

More specifically, there may be different resource type, i.e.DL/UL/flexible/reserved. Depending on the priority, different UEbehavior may be considered.

Regarding relationship between GCCC & dynamic scheduling, the followingpriority may be considered.

(1) Option 1: Dynamic scheduling may always override GCCC.

(2) Option 2: Dynamic scheduling cannot override GCCC for UL resource.In other words, if GCCC indicates UL resources, dynamic schedulingcannot change the UL resources to DL resources. If that occurs, the UEmay assume such resources are not used for DL (e.g. for measurement,data mapping, etc.).

(3) Option 3: Dynamic scheduling cannot override GCCC for DL resource.Similar to Option 2, it may not be possible to change resourcesindicated as DL by GCCC with dynamic scheduling.

(4) Option 4: Dynamic scheduling cannot override GCCC. That is, GCCC mayalways have higher priority than dynamic scheduling.

(5) Option 5: Priority may be configured. Similar to relationshipbetween GCCC and semi-static configuration, the relationship betweenGCCC and dynamic scheduling may be configured per configuration or byhigher layer.

Here, the dynamic scheduling may include DL data scheduling, UL grant,semi-persistent scheduling (SPS) activation/deactivation, anyactivation/deactivation messages. For each channel or type of dynamicscheduling, different behavior may be defined. For example, GCCC mayhigher priority than UL grant, but GCCC may have lower priority than DLscheduling.

When the common signal indicates reserved resource, reserved resourcemay be used for some purposes by additional signaling or dynamic DCIindication or configuration. For example, the reserved resource for eMBBUEs may be used for URLLC. For another example, the reserved resourcemay be used for sidelink operation. For another example, the reservedresource may be used for backhaul links. For sidelink, semi-staticsidelink resource pools may be configured where actual sidelinkresources are considered as available if semi-static sidelink resourcesare indicated as reserved resources or UL resources.

If multiple GCCC or different contents are adopted, priority may beconfigured or determined differently depending on the channel or thecontents. For example, if common signal transmits slot type, option 3described above may be applied. If common signal transmits informationof control region size, the priority may be determined so that commonsignal may have higher priority than semi-static configuration and/ordynamic DCI. One example is that dynamic DCI may indicate startingposition of OFDM symbol for data transmission, and common signal mayindicate the end of control region where data is rate matched orpunctured on the resource where the corresponding control channel ismapped to schedule data.

According to an embodiment of the present invention, signal transmissionlocation in time/frequency is proposed. When GCCC is used, to handle UEswith different radio frequency (RF) bandwidth, separate GCCC may beconfigured per UEs with different RF bandwidth. In other words,different GCCCs may be configured to UEs with different RF bandwidths.Alternatively, GCCC may be transmitted within the smallest bandwidth sothat all UEs can access GCCC. If multiple regions are monitored by UEswith small RF bandwidth, it may be still necessary to transmit multipleGCCCs in different frequency region. UEs supporting larger bandwidth maydetect multiple GCCCS which may have the same contents. Alternatively,GCCC may be transmitted based on nominal RF bandwidth with aggregationlevel L. Aggregation level L/2 may be accessed by UEs with nominal BW/2,and aggregation level L/4 may be accessed by UEs with nominal BW/4. Inother words, based on RF bandwidth, different aggregation level may beused. Alternatively, GCCC may be used only for UEs supporting at least MMHz. M may be prefixed or configured by the network. This may beindicated by the network via RNTI configuration to monitor GCCC. Inother words, GCCC may be monitored based on the semi-staticallyconfigured RNTI value(s).

According to an embodiment of the present invention, control channelformat is proposed. At least for slot type indication, smallest DCI,which may be transmitted over common search space or group-common searchspace, may be used. To minimize the latency of decoding so that commonsignal can be applied to the current slot, the set of candidates wherecommon signal can be transmitted may be restricted to a subset ofcandidates or to the first OFDM symbols of the control region or to thefrequency region among control resource set. To minimize the overhead,aggregation level 1 or 2 may be used for GCCC and further, small sizedcyclic redundancy check (CRC) (e.g. 8 bits) may be used. Depending onthe content, the restriction or the number of blind detections requiredto acquire common signal may be different.

If common or group common search space is shared between common signaland/or other control scheduling common data, and/or transmit powercontrol (TPC) commands and/or fallback DCIs, hashing function of thoseDCIs may need to be adjusted depending on the aggregation level used forGCCC or depending on whether the resource for GCCC is reserved or not.For example, if aggregation level 1 is used for GCCC, hashing functionfor common or group common search space for DCI scheduling common dataor fallback DCI or TPC commands may start at 2nd control channel element(CCE), instead of 1st CCE. Alternatively, to minimize the impact onother DCIs, GCCC may be transmitted in the last CCE or its blinddecoding may be started from the end of CCE (e.g. the hashing functionfor GCCC may be configured as N where N is the number of CCEs in thecommon or group common search space). N may be changed per slotdepending on the control resource set size or common or group commonsearch space configuration. In other words, the mapping of GCCC maystart from the end of CCE (in a reverse mapping). If aggregation levelis larger than 1, the DCI may be mapped to CCE N−1 and CCE N and hashingfunction starts from N−1. If candidates are M with aggregation level L,the hashing function may start at N−M*L+1, where M candidates may besearched sequentially.

Overall, the idea is to map common control search space differently fromother DCI, particularly if aggregation levels are different. Ifaggregation levels are the same, the same search space may be shared aswell. Also different search space may be used if different DCI sizes areused between DCIs scheduling common data or TPC and GCCC. If thereserved resources are used, regardless of the presence of common data,the reserved resource may be rate matched for other controltransmission. To minimize the blind decoding overhead, a set ofaggregation level used for GCCC may be further restricted, i.e.different set of aggregation levels may be configured for GCCC and otherDCIs. More generally, a set of aggregation levels may be configureddifferently per RNTI and/or per DCI format. Also different hashingfunction may also be considered per RNTI and/or per DCI format.Moreover, different control resource set and/or search spaceconfiguration may also be used per RNTI and/or per DCI format. Differentcontrol resource set may be used depending on the knowledge of UE fromthe network perspective. If contention-based PRACH is transmitted, SSfor random access response (RAR) may be used which is shared among UEsusing the same set of PRACH resources (or connected to the used PRACHresource). On the other hand, if contention-free PRACH is transmitted,UE-specific search space (USS) for the UE may be shared for RARtransmission as well.

According to an embodiment of the present invention, application ofcommon signal is proposed. At least one of the following mechanisms maybe applied.

(1) Common signal may be applied to UEs with configured RNTI for GCCC.In this case, common signal may not be applied to cell common data, suchas paging, RAR, SIB, radio resource management (RRM), etc. In otherwords, GCCC may not be applied to UEs in non-RRC connected mode or onlyfor unicast control/data. In other words, in terms of priority orhandling of GCCC, semi-static configuration may always be prioritizedfor common data. For example, paging may always be expected inconfigured paging occasion, RAR may be transmitted in the resource basedon semi-static resource configuration, PRACH may be transmitted in theallocated PRACH resources, PBCH may always be transmitted in theconfigured resources, and SIB may always be transmitted in theconfigured resource. Note that this is from UE perspective, and thenetwork may not transmit data in the configured resource for somereason(s). At least one of the followings may be excluded from applyingGCCC.

-   -   PBCH transmission    -   SIB transmission    -   Paging transmission    -   PRACH transmission    -   RAR transmission (RAR window): For example, if common signal is        also applicable to RAR, RAR window may be configured so that it        counts only valid DL subframes/slots, thus, depending on the        signaling, the actual duration may change.    -   RRM measurement: This may also be applied to neighbor cells. A        set of subframes usable for RRM measurement may be fixed which        may be realized by fixed DL subframe/slots. The configured set        of fixed DL subframe/slots may be always DL slots/subframes,        unless it is explicitly reconfigured to be flexible        subframe/slots. To support this, RRM resource indicated for a        neighbor cell measurement may be considered as fixed DL        resource. To support this, separate measurements may be        exchanged via gNBs. A UE may not be required to monitor GCCC of        neighbor cell to perform measurements.    -   Radio link failure (RLF) measurement    -   Tracking subframes: Similar to RRM, tracking RS transmission may        also occur within the fixed DL subframe/slots.    -   Synchronization signals transmission    -   Fixed common search space: To combine with tracking RS        transmission, a set of subframes may be fixed with common search        space and shared RS transmission may be expected regardless of        common data transmission. If such configuration is achieved,        regardless of common control presence, those signals and        behaviors may be maintained.    -   Periodic CSI feedback measurement    -   Periodic SRS transmission    -   Periodic scheduling request (SR) resource    -   Grant-free PUSCH resources

(2) Common signal may be applied to all RRC_CONNECTED UEs. In this case,a UE may perform different behavior depending on the detection of GCCC.For example, RRM may not be performed in a slot/subframe which isindicated as UL only slot. This may be particularly beneficial ifdifferent RS is used for RRM measurement for RRC_CONNECTED UEs comparedto RRC_IDLE UEs. In this case, depending on the contents of commonsignal, a UE may or may not perform RRM measurement. If sufficientaggregation of RRM measurement may not be achieved due to dynamic changeof slot type, a similar handling to licensed assisted access (LAA)measurement may be used. That is, relaxed measurement may be performedor one-shot measurement may also be considered. The similar approach mayalso be applied to tracking/RLF measurement and if sufficient trackingRS or RLF measurement RS has not been transmitted, the network maytransmit additional tracking RS/RLF measurement RS to support UErequirement.

(3) Common signal may be applicable to all UEs regardless of RRC state.It may be applied to RRC_IDLE UEs or RRC_INACTIVE UEs as well.Particularly in this case, the information about GCCC (frequency, timeinterval, time location, resource configuration, RNTI information, etc.)needs to be indicated by the common data such as PBCH or SIB, so thatall UEs can access the information unless it is fixed in thespecification. To support different UEs with different bandwidth whichare anchored in different frequency regions within the system bandwidth,multiple copies of GCCC may be transmitted. As different UEs havedifferent periodicity to wake-up, the information may be applied onlywithin the slot or next slot or previous slot where common signal istransmitted. Or, if periodic transmission is used, multiple repetitionsof transmissions within one interval may be supported.

(4) Some functionalities may be impacted by common signal regardless ofRRC status, whereas some functionalities may not be impacted by commonsignal. For example, RS/synchronization signal transmission for RRMmeasurement for RRC_IDLE UEs may be transmitted without impacting bycommon signal, whereas RS for RRC_CONNECTED UEs' RRM measurement may beimpacted by common signal or semi-static DL/UL configuration(UE-specific). For another example, PRACH based on contention may not beaffected by common signal, whereas PRACH based on triggered and/orcontention-free may be affected by common signal. In other words, theresources for PRACH for contention based may be indicated as UL resourceby GCCC, whereas PRACH resource for contention-free may be overridden byGCCC. For another example, common search space transmission forRRC_IDLE, DRX UEs may not be affected by common signal, whereas commonsearch transmission for active UEs may be affected by common signal. Foranother example, DRX timer may not be affected by common signal tominimize ambiguity or misalignment between the UE and the network.

Particularly, common signal may affect all UE-specifically configuredresources, whereas it may not affect all cell-commonly or group-commonlyconfigured resources. If this approach is used, grant free resource (ifit is configured in a shared resource manner) may be fixed regardless ofGCCC. One example of such configuration may include sidelink resourceconfiguration or cell-commonly reserved resources. In other words, interms of priority or determining resources availability, certaincell-common resource (which may be configured by SIB or cell-commonsignaling or prefixed) may have higher priority than dynamic commonsignal and/or UE-specific configuration. Another example of suchconfiguration may include PRACH. As CSI-RS may be configured perUE-specific manner, it may be affected by GCCC.

(5) A subset of slots/subframes may be configured in which common signalmay not be transmitted or common signal would may not be affected. Forexample, a set of fixed DL slot/subframes and fixed UL slot/subframesmay be configured, and dynamically slot type may be indicatedperiodically or aperiodically. Even though the slot type may be appliedduring the periodicity between intervals where the signal istransmitted, the configured subframe/slots may be remained the same(i.e. is not affected by common signal). Another example, a set ofsubframes carrying common search space and the shared RS where shared RSmay be present may be configured, regardless of the presence of thecommon search space.

(6) Fallback

When signaling is periodic transmission, if any signaling has not beenreceived during the period, fallback may be done based onsemi-statically configured cell-common or UE-specific configuration orgroup-common configuration. When signaling is aperiodic transmission, itmay temporarily override the semi-statically configured configuration.Otherwise, semi-static configuration is may be applied. Alternatively,regardless of periodic, semi-static, a subset of slots/subframes may beassumed that common signal is not effective. This is for RRM, PRACHtransmission, etc., of RRC_IDLE UEs.

According to an embodiment of the present invention, common signalindication in multi-beam case is proposed. For multi-beam case, at leastthe following aspects may be used with group-specific or cell-specificsignaling. In multi-beam case, GCCC may be transmitted with potentiallybeam sweeping where each beam is transmitted in a subset of OFDMsymbol(s) within a slot. For each beam, the set of OFDM symbol(s) may beconfigured and the set may indicate potential OFDM symbol(s) in whichthe configured beam based GCCC can be transmitted, or exact OFDMsymbol(s) in which the configured beam based GCCC can be transmitted.

In terms of configuration, a UE may be configured with multiple controlresource sets. Each control resource set may be mapped to one or moreOFDM symbols where a UE expects to monitor the configured beam. In otherwords, multiple beams may be configured to the multiple resource sets.For each beam, the maximum or minimum size may be known or prefixed orsemi-statically configured and a UE may expect to monitor multiple ofthis. One control resource set associated with a beam may be calledbeam-control resource set (BCRS). A UE may be configured with one ormultiple of BCRS. In each BCRS, a UE may be configured with one or moreOFDM symbols where the specific beam can be expected. Per each BCRS, thesame beam or different beam may be assigned. For example, different TRPmay be used for each BCRS where different beam is assigned. A UE maymonitor those configured BCRS time/frequency resources for each set. Toallow full flexibility in the network side, the network may configurevery large time resources (e.g. one slot or maximum number of OFDMsymbols where one symbol carries one beam control region). In this case,the UE blind decoding may be considerable.

To minimize the UE complexity, each OFDM symbol configured for BCRS maycarry a signal. The signal may indicate at least one of the followings.

-   -   Beam identity (ID): According to whether the current symbol        carries control signal for a given beam, the signal may be        scrambled with the beam ID to indicate which beam is used in the        current OFDM symbol. If the signal is not detected, a UE may        stop decoding on the target OFDM symbol. Beam ID may be        indicated via CSI-RS resource index and a UE may know        quasi-co-location (QCL) relationship between CSI-RS resource and        each transmission beam via configurations.    -   The presence of GCCC in the symbol: The signal may also be        transmitted with the beam, and if the UE detects the beam, the        UE may attempt to decode the symbol. In this case, the presence        of GCCC or whether the symbol has been used for the GCCC        transmission may be indicated.    -   Beam ID, and number of required blind detections: In addition to        the beam ID, the number of blind detections per symbol may also        be indicated.    -   {Beam ID, DL grant, DL data region part}, and/or {beam ID, UL        grant, UL data region part} and/or {beam ID, associated time        resource}: Another indication may be done to indicate which data        part will be used for either DL or UL depending on the type.        Data region part may be indicated from a pre-configured (via        semi-static signaling) set of possible locations within a slot        or over multi-slots covered by the current control signal.        Common signal between DL and UL scheduling may also be        considered. When time resource is indicated, further scheduling        within that time resource may also be considered.

The following shows a few examples of common signal in multi-beam cases.Single beam indication may be done per beam for the multi-beam case,without loss of generality.

(1) Case 1: Indicate which OFDM Symbol(s) to Read for Control Channel

Beam index for the next few set of OFDM symbol(s) may be indicated ineach OFDM symbol. The frequency of signaling may be either every oneOFDM symbol or every a few OFDM symbols depending on the size of BCRS.

(2) Case 2: Indicate Search Space Blind Detection Candidates in EachOFDM Symbol(s)

The number of candidates where a UE is supposed to perform blinddetection may be indicated in each OFDM symbol. Regardless of beamindex, a UE may search the candidates or it may be combined with beamindex. In terms of signaling, it may be either actual number or ratio ofsearch space or the number of candidates compared to thedefault/configured values.

(3) Case 3: Indicate DL Portion or UL Portion Associated with ControlChannel

When beam index is indicated in the signal, it may also indicate theassociated DL portion or UL portion within a slot or across multipleslots. Whether the signal is done per slot or per multi-slots may beconfigured by higher layer or indicated dynamically in the signaling.The indication may indicate one among pre-configured patterns or sets.Also, the indication may just configure the starting/ending of eachregion. Data region may exist without any associated control region. Inthis sense, it is also possible that instead of signaling associated DLor UL portion with the control beam, the indication may simply indicateDL portion or UL portion within a slot or within multi-slots. Twoinformation may also be indicated independently. By knowing thisinformation, the followings may be applied.

-   -   CSI-RS transmission: CSI-RS position may be fixed relative to        the end of DL portion. If DL portion changes due to some        reasons, e.g. reserved resource or UL resource, the actual        position of CSI-RS may be changed. Alternatively, CSI-RS may not        be transmitted within a unit (slot or multi-slot depending on        the configuration) if DL portion size is smaller or it does not        cover CSI-RS position.    -   SRS transmission: Similar to CSI-RS, SRS may be fixed relative        to the start of UL or end of UL portion. Or, UL portion size may        determine whether to transmit SRS or not.    -   Any periodic RS: If tracking RS is adopted, similar to CSI-RS,        different approaches may be considered.

In terms of duration, it may be determined implicitly based on the OFDMsymbol index in which control is carried. For example, the DL or ULportion per beam may be virtually divided based on the maximum number ofbeams per slot/multi-slot, and the index of control channel in terms ofOFDM symbol may be used for the index for the DL or UL portion withinslot/multi-slot.

(4) Case 4: Indicate Beam Index Used in Control Channel

Simply, beam index used for the OFDM symbol(s) may also be indicated.

(5) Case 5: Activate or Deactivate any Semi-Statically ConfiguredInformation

Another approach is to allow opportunistic signal which may activate ordeactivate the semi-statically configured information. The activation ordeactivation may be applied only to the slot/multi-slot where the signalis applied or the effectiveness can continue. In case of the latter, thereliability may become an issue which requires repeated signaling. Inthis sense, when opportunistic signaling is used, it may be restrictedonly to the slot/multi-slot (i.e. temporary activation/deactivation).For example, temporary deactivation may also be transmitted, and a UEmay expect that periodically configured CSI-RS or SRS transmission mayoccur if the deactivation signal is not detected (or temporaryactivation may also be considered). This is to support temporaryresource blanking due to some coordination or handling forwardcompatible resources, etc. Similarly, for semi-statically configuredOFDM symbols for a beam index for control channel monitoring, if anysignal to deactivate the symbol is detected, a UE may skip decoding onthe symbol.

(6) Case 6: DL/UL Pattern within a Slot/Multi-Slot

Which DL/UL pattern is used within a slot or multi-slot may beindicated. For example, if one slot or multi-slot is divided to foursmall mini-slots, DL/UL configuration (e.g. 2:2) may be indicated bycommon signal per each beam.

FIG. 5 shows an example of indicating which DL/UL pattern by commonsignal according to an embodiment of the present invention. In FIG. 5, aUE is configured with a set of BCRS. In each BCRS, at least one of abeam index, frequency/duration location of SS, a number of candidates orrelated hashing function may be indicated. Further, in FIG. 5, two slotsare divided to control region and four small mini-slots. In this case,DL/UL pattern (or, configuration) may be indicated.

The beam index discovered/used during beam management/initialization maybe used for control channel.

When beam index is signaled, a channel/signal may carry more than onebeam indices as the signal can be targeted for more than one beam. Forexample, for UEs without DL/UL scheduling, control channel monitoringmay not be necessary. However, some indication (e.g.activation/deactivation) may be useful. To support this, beam indicesmay be grouped and the signal may be transmitted per beam group insteadof per beam. Indication of activation/deactivation or other commonchannel/signal may be transmitted in addition to this signal. Forexample, the first signal may indicate whether there will be somecontrol channel/signals in the current OFDM symbol. This may be done bytransmitting beam group or beam ID in each OFDM symbol (based on theunit size where the signal is transmitted, in each OFDM symbol or everya few OFDM symbols). Once it is detected, additional control may includenecessary additional information (e.g. activation/deactivation) perbeam.

Single beam case may be treated as a special case of multiple beam casewith one beam. In other words, all mechanisms applicable for multiplebeam case may also be applicable to single beam case.

According to an embodiment of the present invention, common signalindication in single beam case is proposed. Similar purpose of commonsignal to multi-beam case may be considered for single beam case. Inmulti-beam case, beam index may be used as a group index. In single beamcase, separate group ID, which may be divided per subband or per UEgroups depending on usage scenarios, etc., may be defined. Furthergrouping within a beam or beam grouping in multi-beam may also beconsidered.

Applying to both single beam case and multi-beam case, one motivation toadopt common signal is to indicate resource allocation type and/orgranularity.

According to an embodiment of the present invention, the relationshipamong beams is proposed. In the present invention, it was mentioned thatbeam index may indicate whether the UE is supposed to read controlchannel or to indicate some possible DL or UL region associated with thebeam index. However, actual information to indicate beam index may bedifferent depending on various operation. The followings may be a fewexamples to indicate beam index.

-   -   Alternatively, in multi-beam case, the resources may be defined        for GCCC with beam index(s) that a UE is configured to monitor.        Otherwise, the resources may be considered as flexible resources        unless the UE is scheduled. In that sense, some semi-static        configuration may not be valid in flexible resources if they are        configured to do so.    -   CSI-RS resource index: If a UE is configured with multiple        CSI-RS resources and data transmission occurs associated with        one or more CSI-RS resources, similarly, CSI-RS resource may be        associated with control channel. In other words, a UE may be        configured with one or more CSI-RS resource indices which are        monitored by the UE. Different CSI-RS resource may be configured        with different characteristics such as TRP identity, different        blank resource set (semi-statically configured), control        resource set configuration (time-domain only or frequency-domain        only or both time/frequency domain). For common search space,        default CSI-RS configurations/resource indices may be used, or        no explicit configuration may be used.    -   Beam index from measurement RS: Beam index used in measurement        RS may be used as beam index of control channel. The measurement        RS may be either based on reference signal or synchronization        signals.    -   Beam index from OFDM symbol where the corresponding beam        precoded measurement RS is transmitted: Symbol index or SS-block        index in which synchronization and/or measurement RS has been        transmitted with the corresponding beam may be used as beam        index of control channel.

More specifically, the following may be some procedure to acquire beamindex for control channel monitoring, and its associated feedback.

(1) Multiple SS-blocks may be transmitted and each SS-block may containa single beam. Based on initial cell search and measurement based onsignals transmitted in each SS-block, a UE may determine besttransmission (TX) beam(s) and the corresponding reception (RX) beam(s)for each best TX beam. The beam index may be inferred from the locationof SS-block, index of SS-block, or separately indicated by eachSS-block. In this case, a UE may assume that the selected best TX beammay also be used for control channel monitoring. For common searchspace, a UE may be expected to monitor control channel in given TX/RXbeam pair(s) which are discovered during initial access. The beam pairfor each common search space for initial access may be configured asfollows.

-   -   RAR: Reciprocity may be assumed or not. When reciprocity is        assumed, corresponding RX beam based on TX beam may be used for        PRACH transmission, and the TX beam selected for PRACH        transmission may be used for RAR reception. For RX beam to        receive TX beam, the best RX beam selected by the UE in the        initial access procedure or synchronization signal detection        procedure, or already known RX beam may be used for the given TX        beam.    -   Msg 3: TX beam of a UE may be explicitly indicated by RAR or a        UE may select the best beam similar to beam selection for PRACH.        The RX beam to receive Msg 3 may also be determined based on        PRACH/RAR procedure. The UCI transmitted with Msg 3 may be        transmitted with the same beam direction or may follow PRACH        beam direction. If the beam index for Msg 3 is explicitly        indicated and UCI and PUSCH transmission occur independently,        the beam used for PUSCH and UCI transmission may be different,        and UCI may be transmitted to the same beam index where PRACH        has been transmitted. If PRACH has been transmitted with        multiple beams, UCI may be transmitted only with the best beam.    -   Msg 4: Without any further configuration, the same beam index        may be used between RAR and Msg 4. With HARQ-ACK feedback on Msg        4, Msg 3 may carry CSI feedback which may be used to further        refine the beam for each UE. Thus, the beam index used for the        UE may be further reconfigured after or during Msg 4.

(2) SS block index may be defined, and SS block index may indicate theassociated RAR/Msg4 timing TX/RX beam pair implicitly without anyfurther association. Prefixed timing relationship between PRACH TX beamand RAR TX beam may exist so that a UE can expect to receive RAR TX beamin a certain position without further configuration. Similarly, beamused for PRACH/Msg 2 may be used for Msg 3/4. For Msg 4 search space,fixed timing between Msg 3 to Msg 4 may be used. Thus, a UE may not needto monitor multiple search spaces. Or, common signal mentioned in thepresent invention may be used to indicate beam index used in each SS sothat a UE can skip decoding if the beam index is not matched to thecorresponding beam.

(3) The same beam used for PBCH reception or the beam associated withPRACH (i.e. TX beam from gNB corresponding to PRACH TX beam from UE) mayalso be used for control channel reception at least for common controldata. For PBCH, if it is different from synchronization signal, it maybe indicated by the UE. This value may be used as a default value untilreconfiguration occurs.

FIG. 6 shows an example of a procedure acquiring a beam index accordingto an embodiment of the present invention. When reconfiguration isoccurred for the USS, or group search space, in each search space,associated beam index (or CSI-RS resource index) may be indicated. A UE,by configuring one or multiple of search space or resource set, maymonitor one or multiple beam. For each beam index (or CSI-RS resourceindex), The UE may know the best RX beam via beam management. In termsof search space or resource set configuration, a UE may be configuredwith time-resource or time-resource which is the maximum controlresource set in time.

More specifically, beam index or beam used for control transmission mayconsist of subset of CSI-RS resource. For example, 1 or 2 ports ofCSI-RS may be used for control transmission, or a certain precoding maybe used. In either case, the number of ports may also be configured pereach control resource set. This may be useful when spatial multiplexingis applied among different control channels. When beam index or relatedinformation is not configured, a UE may assume that beam indexdiscovered during initial access procedure may also be used for controlchannel or single beam is used in the network.

Hereinafter, various aspects of GCCC are proposed according toembodiments of the present invention.

1. Physical Channel Used for GCCC

When GCCC is transmitted and/or received opportunistically, it may notbe desirable to prefix the resources for GCCC. As control channeldecoding may occur after detection of GCCC, if GCCC is transmitted inpredefined resource, GCCC may puncture control channel. Or, the presenceof GCCC may be implicitly determined by detection of GCCC, and dependingon the presence of GCCC, the mapping of control channel may bedifferent, i.e. control channel may be rate matched or resource elementgroup (REG) mapping may be changed.

Alternatively, GCCC may be transmitted via group search space or cellcommon search space or UE-search space. In that case, aggregationlevel(s) for GCCC may be configured via higher layer or broadcastconfiguration (e.g. SIB). This may be particularly useful if the size ofGCCC contents is quite different from other DCI sizes (and thus increasethe number of blind detections). Furthermore, when reliabilityrequirement between regular DCI and GCCC is different, differentaggregation level seems necessary. Lastly, it may also be useful whenGCCC is mapped to the partial OFDM symbols in the control region of SSwhere GCCC may be transmitted. If multiple OFDM symbols are configuredto SS where GCCC is also transmitted, the mapping of GCCC may berestricted to the first one or two OFDM symbols to reduce the latency.In this case, the following mechanisms can be considered.

-   -   Regardless of control region size of SS where GCCC can be        transmitted, GCCC may always be mapped to one or two symbols        only. In other words, in case of GCCC mapping, except for one or        two symbols, control channel may be rate matched in other OFDM        symbols. As it may reduce the available resources in which GCCC        is mapped, increased aggregation levels may be used. The        aggregation level may also be increased automatically. For        example, if control region spans two OFDM symbols whereas GCCC        is mapped to one OFDM symbol, and REGs in a CCE are rather        uniformly distributed within control region, aggregation level        for GCCC may be doubled to compensate resources mapped in second        OFDM symbol. This may also be addressed by explicit higher layer        configuration of aggregation levels used for GCCC.        Alternatively, when GCCC is configured, the number of OFDM        symbols where GCCC can be mapped may be configured by higher        layer. Depending on the information, the aggregation levels may        be automatically defined. If the number of OFDM symbols where        GCCC can be mapped to is the same as control region size, the        same set of aggregation levels configured in SS may be used for        GCCC as well. Or, the same set of aggregation levels for group        common search space may be used for GCCC. If smaller number of        OFDM symbols are used compared to the search space, aggregation        levels may be doubled, and extra aggregation level may be        monitored.    -   Separate resource set may be configured for GCCC    -   Different REG-CCE mapping (restricted to one or two OFDM        symbols) may be considered.

2. Handling Carrier Aggregation (CA) Environments

In NR, different CA environments may be considered as follows.

(1) DL and UL may be configured from different frequency band. Fromcarrier frequency band perspective, though a UE is served via only onecarrier, DL and UL may be treated as if they are carrier-aggregated.

(2) Multiple carriers may be aggregated to support wideband operation

(3) Inter-frequency band or intra-frequency band CA may be considered.

When CA is used, transmission of GCCC becomes a bit more challenging,particularly when a UE does not monitor common or group common searchspace in secondary cell (SCell). Particularly, when different carrier isconfigured for DL and UL separately, as different UEs may be configuredwith different UL carrier though they share the same DL, the commonsignal needs to be clarified. The following mechanisms may be consideredfor CA environments.

(1) When group common search space or GCCC is transmitted, separate GCCCmay be transmitted per DL/UL pair. Different DL/UL frequency band may beconfigured. However, this may lead excessive overhead if UEs areconfigured with different DL/UL frequency bands.

(2) Common signal may be transmitted separately for DL carrier and ULcarrier. For DL carrier, same-carrier scheduling/transmission may beused, whereas for UL carrier, cross-carrier scheduling/transmission maybe used.

(3) Common signal may be transmitted only for self-carrier so that anycommon signal is not supported for the cases of cross-carrier schedulingor different DL/UL carrier combination. This may also include FDD case.For FDD case, the paired DL and UL may be the same carrier from GCCCscheduling/transmission perspective. In this case, even though a UE isscheduled with cross-carrier scheduling, for common signal, the UE canmonitor group common search space in self-carrier. Further in this case,if UL is in different frequency band, unless the pairing is specified asa cell-common pairing by broadcast signaling e.g. via PBCH/SIB, anysignaling on UL carrier may not be supported. If different frequencyband paring between DL and UL is achieved via cell-common broadcast, thesignaling may be interpreted for the paired UL as well. UEs configuredwith different UL carrier from cell-common paired DL-UL may ignoreconfigurations related to UL.

(4) Common signal may be transmitted either via self-carrier schedulingor cross-carrier scheduling. Separate or combined indication formultiple carriers may be possible. If GCCC is configured only in asubset of carriers among configured aggregated carriers, the signalingmay include information for multiple carriers.

Particularly for intra-band CA, the same configuration applies to theall carriers in the same frequency band if a UE is indicated that theconfiguration may be the same. In other words, if the network configuresthe same configuration among intra-band carriers, the network may informUEs about it, and the UE may assume the same configuration. This may bedone by mapping configuration of multiple carriers to the same entry ofslot formation indication (SFI) when multiple SFIs are given by GCCC.Otherwise, a UE may not assume the same configuration. Particularly,fixed DL subframes/slots may be different per carrier even in case ofintra-band CA.

More specifically, if a UE is configured with multiple UE-specificcarriers on a carrier from the network perspective, a UE may monitorGCCC in one UE-specific carrier (or subset UE-specific subcarriers) ofconfigured UE-specific carriers. The UE may assume that the sameconfiguration applies to other UE-specific carriers. Even when a UEmonitors GCCC on multiple UE-specific carriers within a carrier, thesame configuration may be used unless some advanced feature (such asfull duplex or FDM between DL/UL is supported) is used or unlessotherwise indicated. In this case, even though a UE may be configuredwith multiple DL UE-specific carrier, the UE may be only configured withone UL UE-specific carrier. For not-configured UL UE-specific carriers,information carried over GCC may be ignored. If a UE is configured in aDL UE-specific carrier and corresponding UL UE-specific carrier is notconfigured, the information from GCCC regarding UL may be applied to theconfigured UL UE-specific carrier. If different configuration is appliedin each UE-specific carrier, the UE may assume that network canconfigure proper UE-specific carrier for GCCC monitoring. TheUE-specific carrier where GCCC is monitored may be configured by higherlayer to a UE or group of UEs, particularly when a UE is configured withmultiple UE-specific carriers within a NR-carrier. This may be done byconfiguring mapping between SFI in GCCC (such as one entry in multipleentries in the channel) and one or more carrier indices configured to aUE. In other words, this mapping may be UE-specific. If mapping is notgiven, a UE may assume that self-carrier with the associated DL/UL inunpaired spectrum is mapped.

Furthermore, a UE may be configured with multiple carrier groups forGCCC. In each carrier group, the same configuration may be assumed,including slot type indication from GCCC and/or fallback configuration.When carrier groups are configured, which carrier is used fortransmission of GCCC may also be configured. In other words,representative carrier to transmit GCCC may be additionally indicatedper carrier group.

(5) When GCCC transmission is not available due to cross-carrierscheduling configuration or different UL frequency band configuration,etc., the UE may assume that semi-static configuration may always beapplied and possibly assisted by UE-specific dynamic signaling. If thatis not available, the carrier (UL carrier only or DL carrier only orDL/UL carrier) may not be configured with GCCC, and the resources may beflexible.

(6) Common signal at least for slot type indication may be transmittedonly for TDD carriers. If flexible duplex operation is achieved in FDDUL spectrum, common signal for UL where TDD operation is achieved may betransmitted. Other common signal may be transmitted for DL or UL or bothDL/UL depending on the contents. For example, in case of puncturingindication, it may be more desirable to indicate only for DL, and thesize of control region may also be indicated only for DL.

When supplemental UL (SUL) carrier is configured for a DL/UL carrier,GCCC may be separately transmitted between DL/UL carrier and SULcarrier. When different numerology is used between DL/UL carrier and SULcarrier, the followings may be considered for SFI for SUL carrier.

-   -   Slot format may be based on DL carrier where SFI is transmitted.        Accordingly, slot type for SUL carrier may be determined (e.g.        if 2 OFDM symbols of 15 kHz subcarrier spacing in DL is used, 4        OFDM symbols of 30 kHz subcarrier spacing in SUL carrier in DL        is used).    -   Slot format may be based on SUL carrier which may be configured        to the UE. In terms of interpreting slot format for SUL,        numerology of SUL carrier may be considered.    -   Similar handling may also be assumed when DL and UL use        different numerologies.

In other words, when DL and UL uses different numerologies, separate SFImay be transmitted to DL and UL respectively, even in unpaired spectrumcase.

Overall, for DL, GCCC may be applied to the DL carrier if self-carriertransmission is used, and/or the same carrier in which GCCC istransmitted if cross-carrier scheduling is used (for GCCC itself),and/or the indicated DL carrier by cross-carrier scheduling, and/or allDL UE-specific subcarriers within a NR carrier, and/or all DL carriersin contiguous intra-band carriers. For UL, GCCC may be applied to ULcarrier if self-carrier transmission is used, and/or the paired ULcarrier by cell-common signaling and/or by specification with DL carrierin which GCCC is transmitted, and/or all UL UE-specific subcarrierswithin a NR carrier, and/or all UL carriers in contiguous intra-bandcarriers. For cross-carrier scheduling, separate carrier index may beused for DL and UL, and thus cross-carrier for UL may also be possibleindependently from DL carrier. Or, the paired UL carrier for the DLcross-carrier scheduled carrier may be used. If latter is used, carrierindex may be used for DL-UL paired carrier or DL only carrier. In caseof TDD on the same frequency band, the same frequency may be paired inthe same frequency. If cross-carrier scheduling of GCCC is adopted, anddifferent numerology is used between scheduling and scheduled carrier,the scheduling may be done in the first slot, where slot boundarybetween carriers are aligned only. Or, if scheduling occurs in themiddle of slots corresponding to one slot with smaller subcarrierspacing, the configuration may be applied in the next slot.

According to an embodiment of the present invention, handling CA andcross-carrier scheduling case is proposed. When slot type indication isconsidered which involves both DL and UL, some clarification may benecessary, particularly if different UEs are configured with differentUL carrier while sharing the same DL carrier. For example, as discussedin LTE-NR coexistence, LTE UL spectrum for NR UL transmission may beutilized to achieve better coverage. In that case, instead of utilizingpaired UL spectrum or the same spectrum to DL spectrum, a UE may utilizedifferent UL spectrum. In such a case, whether a UE can assume theindicated slot type also to UL spectrum or not needs to be clarified.Furthermore, when a UE is configured with cross-carrier scheduling for acarrier, whether GCCC can be transmitted from the same carrier orscheduling carrier needs further discussion.

3. Fallback Behavior

When slot type is indicated via common signal, fallback operation needsto be clarified. As slot type may include different length of DL, UL,reserved portions, fallback configuration needs to be carefullyconsidered, particularly for UL transmission. The following mechanismsmay be considered.

(1) Dynamic signaling may indicate larger DL portion, and may indicatethe same UL portion compared to fallback configuration. For DL, a UEwithout detecting the common signal may miss RS transmission on theincreased DL portion by dynamic signaling. If a UE is configured withaperiodic CSI-RS reporting, a UE may assume that CSI-RS is transmittedeven though it misses the dynamic common signaling, and fallbackconfiguration may indicate no potential measurement RS transmission inthe slot.

(2) Dynamic signaling may indicate smaller DL portion, and may indicatethe larger UL portion compared to fallback configuration. For DL, a UEwithout detecting common signal may assume that RS transmission mayoccur in the slot. As the network has not transmitted RS in the slot, itmay affect measurement performance of the UE. Particularly for RS usedfor aggregated measurement such as RRM, periodic CSI-RS, RS transmissionmay occur in the fixed DL portion and fixed DL portion may not bechanged by the dynamic signaling. In other words, there may be someoverlapped portion for DL between fallback configuration and dynamicsignaling so that a UE may assume that the UE wrongly detects commonsignal if the common signal indicating fixed DL portions are changed toeither UL or reserved.

For UL, a UE may assume that a long PUCCH format may be transmitted ifcommon signal has been received. Otherwise, the UE may assume that ashort PUCCH format may be transmitted. If PUCCH format is dynamicallyselected depending on slot type, some further considerations may benecessary. For example, long PUCCH format may be designed so that it maybe rate matched around short PUCCH resources. Alternatively, to addressmissing case, long PUCCH format may be triggered only if UL only or ULheavy slot type are semi-statically configured, which may not be changedby the dynamic signaling or by dynamic indication in the scheduling (inother words, DL scheduling DCI may also include PUCCH format betweenlong and short). If long PUCCH resources are reserved, a set ofsubframes/slots may be UL-centric/heavy or UL slots. In terms of dynamicsignaling indication, such resources/slots may always be indicated as ULcentric or UL slot. However, the network may change the slot toDL-centric or DL-heavy as there are no expected PUCCH transmission.Thus, for UL, it may not be so essential to assume that a subset ofsubframes are fixed to UL-centric or UL slot. Regardless ofconfigurations, a UE may assume that a slot type is UL-heavy or UL iflong PUCCH is configured to be transmitted. As different size of longPUCCH format may be used in different length of UL portion, when longPUCCH format is configured, the size of long PUCCH format may beconfigured. Alternatively, when DL transmission occurs, the exact lengthor format of long PUCCH may also be indicated, and the network mayconfigure a set of PUCCH formats including long PUCCH formats andindicate dynamically the exact format. If multiple ACK/NACKs aretransmitted on the same format, the same format may be indicated in eachDL transmission.

(3) Dynamic signaling may indicate all DL, whereas fallbackconfiguration may include UL portion. It is possible that a UE scheduledwith periodic SRS, etc., may transmit in the slot if it misses commonsignal.

(4) Dynamic signaling may indicate all UL, whereas fallbackconfiguration may include DL and UL portions. It is possible that a UEexpects some DL measurement RS transmission in the slot if it missescommon signal and measurement RS is configured to be transmitted in theslot.

(5) Dynamic signaling may indicate reserved resource, whereas fallbackconfiguration may include DL and UL portions. It is possible that a UEexpects some DL measurement RS transmission in the slot and/or a UE mayalso transmit any scheduled UL transmission such as SRS if it missescommon signal and measurement RS is configured to be transmitted in theslot.

In terms of making fallback configuration, the following approaches maybe considered.

(1) Semi-static DL/UL configuration (e.g. LTE TDD DL/UL configurationswith special subframe configuration) may be used. If common signal ismissing, the slot may be considered as either DL or UL or specialsubframe. In this case, reserved resource may be protected only byscheduling.

(2) DL slot may be assigned as slot which requires fallbackconfiguration due to common signal missing. In this case, a UE mayassume DL measurement even though the network may not transmit any DLtransmission. This may lead inaccurate measurement performance. In thissense, if this approach is used, it is highly desirable that measurementis transmitted in fixed DL portions which may not be altered by commonsignal. To minimize the case of mis-computation of measurement, it isalso possible that only minimum DL portion may be able to schedule DL.Data may be scheduled where a UE may further assume more DL resourcesavailable by the scheduling. To minimize the case of non-transmission ofUCI, it may also be possible that minimum UL portion is also assumedwhere if a UE is scheduled ACK/NACK in the slot, it may transmitACK/NACK.

(3) UL slot may be assigned as slot which requires fallbackconfiguration due to common signal missing. If a UE behaves differentlyin UL slot compared to UL-centric or DL-centric (e.g., use differentPUCCH length, PRACH format, etc.), it may be necessary to designPUCCH/PRACH used in UL slot not to interfere with PUCCH/PRACHtransmission in UL-centric/DL-centric. For example, separate resourcesfor PUCCH/PRACH transmission may be configured depending on thelength/format.

(4) Reserved slot may be assigned as slot which requires fallbackconfiguration due to common signal missing.

(5) Semi-static DL/UL configuration or DL/UL slot type may be configuredto a subset of slots and fallback may occur following the semi-staticconfiguration. In other slots/subframes, one of option (2), (3) or (4)mentioned above may be used.

(6) Semi-static DL/UL slot type configurations may be used. Similar toDL/UL configuration, a set of slot type for each slot over multipleslots may also be configured semi-statically.

More specifically, when a UE is configured with long PUCCH format in acarrier and slot type may be dynamically changed, the followingmechanisms may be considered.

(1) A UE may transmit long PUCCH format in a slot based on PUCCH timingconfiguration regardless of common signal indication and/or semi-staticconfiguration. In other words, if the UE is indicated to transmit longPUCCH format, regardless of common signal/fallback operation, the UE maytransmit long PUCCH format in a given slot.

(2) A UE may transmit long PUCCH format only in a slot which areindicated as UL-centric or UL slot by dynamic signaling (or by fallbackoperation if dynamic signaling is missing). Otherwise, a UE may switchto short PUCCH format or skip PUCCH transmission.

(3) A UE may transmit long PUCCH format only in configured subset ofslots which are configured that they can carry UL centric channels suchas long PUCCH format. In other slots, regardless of slot type, a UE maytransmit short PUCCH format. Alternatively, a UE may be configured witha subset of slots/subframes in which long PUCCH format may betransmitted (and/or short PUCCH may be transmitted).

(4) Fallback configuration may be always be followed for long PUCCHformat. For dynamically changed UL-centric slots, long PUCCH format maynot be allowed (i.e. short PUCCH format is rather used).

(5) Different size of long PUCCH format may be used following fallbackconfiguration. The maximum UL portion granted by fallback configurationmay be used for PUCCH transmission in each slot. If more UL portion isgranted by GCCC, the extra UL portions may be used for non-PUCCHtransmissions (e.g. aperiodic SRS, PUSCH, etc.). This is particularlyapplied if PUCCH length is semi-statically configured or PUCCH length isnot dynamically changeable. This may be true even if fallbackconfiguration is not given for DL/UL slot type in general.Alternatively, PUCCH length in each slot may be semi-staticallyconfigured. A set of slots used for long PUCCH format with a certainlength may be configured and multiple sets of such list may beconfigured to a UE or group of UEs or cell-specifically.

(6) PUCCH length may be dynamically indicated by DL scheduling DCI, andthe UE may always follow length indicated by DL scheduling. GCCC mayindicate smaller or larger UL portion which may be lower prioritycompared to dynamic indication. In other words, a UE may not expect thatPUCCH resources are indicated dynamically in a resource which isindicated as either DL resource or unknown resource by GCCC. Similar todynamic DCI, this may always be assumed that the same information bydynamic signaling are used. Semi-static resources, such as SR, CSIfeedback, or HARQ-ACK for SPS corresponding (if any), may be overriddenby dynamic GCCC. In that case, if length of the semi-staticallyconfigured PUCCH resource is larger than the indicated UL resource byGCCC, it may be considered as invalid resource. Or, multiple PUCCHformats may be configured and one format which has the largest lengthfitted within the indicated UL resource may be selected.

Alternatively, fallback option may be different depending on how theindication is utilized. If GCCC is for neighbor cell's interferencehandling, a UE may use DL slot for fallback option when GCCC is missing.

Fallback example is as follows. Unless the signaling is purelyadditional signaling, some fallback behavior needs to be defined tohandle GCCC missing case. One example of fallback operation is to usesemi-statically configured slot types, which are applied/assumed if GCCCis missing. Furthermore, if slot type indication changes the duration ofUL portions, it needs to be clarified how PUCCH is transmitted. Oneapproach is to assume that fallback configuration is always subset ofdynamically indicatable UL portions (unless it is configured as DL onlysubframe) so that a UE may transmit PUCCH on the resource followingfallback configuration. If this approach is used, regardless of ULportions configured by GCCC, limited UL resources may available forPUCCH transmission.

FIG. 7 shows an example of fallback operation according to an embodimentof the present invention. Referring to FIG. 7, regardless of GCCCindication on slot type, PUCCH region may be unchanged to avoid anyambiguity between the network and UEs. Also, it may be desirable thatdynamic PDCCH does not indicate any UL portion smaller than PUCCHregions.

For the fallback configuration, smallest DL and smallest DUL portion maybe configured and other portions may be left as flexible so thatflexible resources may be indicated by the network for data & otherscheduling. If this is used, for DL measurement, measurement RS may needto be transmitted in the smallest DL to avoid any ambiguity. Differentslot may have different fallback slot type, and smallest DL and smallestUL may be used for a slot with DL and UL. In flexible resource,resources indicated dynamically may be valid, and some semi-staticconfiguration may also be considered as valid (or depending onconfiguration, the default behavior may also be configured whether toassume valid or invalid) under the fallback condition.

4. Resource Configuration for Common Signal

Assuming periodic or aperiodic transmission of GCCC, GCCC may betransmitted via common search space or group common search space.Aggregation level used for GCCC may be further restricted to the maximumaggregation level considering the reliability. In a wideband system,there may be multiple duplicate common search space and different UEsmay monitor different common search space due to its limited bandwidthor bandwidth adaptation operation, etc. A UE which may monitor multiplecommon search space or resources simultaneously may acquire multiplecopies of GCCC or may be configured to monitor only one common searchspace. If a UE may acquire multiple copies, the content needs to be sameacross different subbands in the wideband. As different subband may beequipped with different slot structure and/or numerology and/or resourceallocation in DL, UL, guard period, and/or reserved resource, therelationship between GCCC and its effective bandwidth needs to beclarified. The following approaches may be considered.

(1) The wideband may be divided to a few subbands and each subband mayhave independent cell-specific search space (CSS). GCCC may be carriedin each subband. GCCC may be applied to resources in the correspondingsubband only.

(2) There may be multiple resource sets for CSS and a UE may beconfigured with one resource set for CSS for GCCC. Along with theresource set configuration of CSS, the resource region where GCCC iseffective may also be configured. Unless otherwise indicated, GCCC maybe applied to the entire system bandwidth.

In either approach, a UE needs to be configured with search space inwhich GCCC can be monitored and the resource in which GCCC is applied,implicitly or explicitly.

Another issue is whether a UE is required to monitor common search spaceor group common search space for GCCC in every subframe, regardless ofwhether a UE is configured with a subset of slots for controlmonitoring. The following approaches may be considered.

(1) A UE may monitor GCCC only in slots in which CSS/group search space(GSS) is configured to be monitored.

(2) A UE may monitor GCCC separately from CSS/GSS. In other words, if aUE needs to monitor GCCC in every slot, regardless of control resourceset or search space configuration, the UE may monitor CSS/GSS in everysubframe or configured resources for monitoring.

Further, monitoring slot may be configured differently per resource setand/or search space.

In a wideband, due to small bandwidth supported compared to thewideband, there may be different subbands defined and different UEs maymonitor different subbands. For example, if system bandwidth is 400 MHz,and a UE can support nominally up to 100 MHz, there may be 4*100 MHz inthe system. To simplify the design, UE bandwidth X (e.g. 100 MHz) may beassumed to be nominal. UEs supporting smaller than X may not beoptimized in the system design.

The bandwidth partitioning or subband formation may be propagated byPBCH and/or SIB. In terms of partitioning, the size may be defined as X.In each subband, synchronization signals for cell detection andnecessary RS transmission for measurement may be transmitted. PBCHand/or SIB may also be transmitted to support PBCH/SIB update withoutrequiring retuning of a UE to different frequency. For each UE, searchspace or control-resource set (CORESET) where the UE may monitor GCCCmay be configured.

FIG. 8 shows an example of subband formation according to an embodimentof the present invention. Referring to FIG. 8, in each subband withbandwidth X, synchronization signals and/or PBCH/SIB may be transmittedwith potentially different frequency, sequence. If X is small, there maybe subbands without additional synchronization signals.

CSS in each subband may be configured so that all UEs can monitor theCSS in the configured subband. If there are UEs with smaller bandwidth,small bandwidth CSS may be configured. Also, if a UE can access multiplesubbands, one of CSS may be configured to the UE as the primary searchspace. Also, the resource allocation or resource region where CSS coversmay be indicated. This is particularly necessary when GCCC istransmitted separately per subband, and a UE which can access more thanone subband may listen only one CSS. A UE may be configured that GCCCfrom the CSS can cover multiple subbands or not. Alternatively, a UEneeds to receive GCCC from each subband.

When a subband is defined, an anchor subband may carry initial SS blockwhich can be accessed by RRC-IDLE/INACTIVE UEs as well. For othersubbands, additional SS block may be transmitted with differentperiodicity or same periodicity compared to initial SS block.

The information of subband compared to SS block may be known/indicatedto the UE, and resource may be allocated based on subbands where a UEmonitors. In terms of resource allocation/scrambling, the followingoptions may be considered.

(1) PRB indexing may be done locally within a subband. A UE accessingmultiple subbands may have resource allocation over multiple subbandswith subband index, and scrambling may be done separately per eachsubband.

(2) PRB indexing may be done per system bandwidth, and scrambling may bedone locally. In terms of resource allocation, different number of PRBsmay be allocated based on the configured subbands of a UE. And dependingon the allocated bandwidth, different UEs may have different startingphysical RB index even though they are monitoring the same subband.

(3) PRB indexing and scrambling may be done in system bandwidth.Considering that system bandwidth may not be known to UEs, PRB indexingmay be done based on indication to a reference point (e.g. virtual PRB0) assuming some virtual maximum RBs of system bandwidth.

CSS, particularly CSS where a UE monitors GCCC, fallback, TPC, etc., maybe configured by MIB/SIB or UE-specific signaling when reconfigurationof subband occurs. Alternatively, the same configuration of CSS may bepresent in every subband, and a UE may assume the same configurationfrom the anchor subband CSS configuration except for the physicalfrequency location, and thus, no additional information may benecessary. The CSS in a subband, though, may be reconfigured viaPBCH/MIB. If PBCH/MIB reconfigure CSS for a subband, there may be thefollowing two mechanisms.

(1) PBCH/SIB in each subband may carry all information of all subbandCSS so that a UE can acquire the information from any PBCH/SIB of asubband.

(2) PBCH/SIB in each subband may carry information of the given subbandCSS only so that a UE needs to retune to different subband to acquirePBCH/SIB.

In PBCH/SIB, the information of synchronization signals and/or PBCH/SIBtransmission of subbands may be indicated so that a UE can acquirePBCH/SIB from the given PBCH/SIB. All the information includingconfiguration of CSS may also be given by UE-specific configuration whenretuning occurs. But subband PBCH/SIB may carry different information ofCSS. If different PBCH/SIB is transmitted, SIB update may still beapplicable to all PBCH/SIBs of all subbands. A UE may acquire PBCH/SIBin any subband, as the contents are basically same with some differentoptions in terms of subband size, CSS configuration, etc., which arespecific to subband. Whenever a UE switches subband, the UE may requireto acquire such subband-specific information again.

FIG. 9 shows an example of CSS formation according to an embodiment ofthe present invention. FIG. 9 assumes the same configuration as FIG. 8.PRB indexing can be based on SS block, as least when PRB indexing occurslocally. The RB indexing may start from the center of SS block or PSS,and may be expanded to the subband size. When a UE is reconfigured withdifferent subband, the center location of SS block or center of PSS maybe indicated with subband size, which may define the resource mapping inthe configured subband as well. Due to channel raster, it may not bepossible to place SS block within a center of a subband. If those casesare considered, based on indicated direct current (DC) subcarrier orcenter of an anchor subband from PBCH/SIB, resource block may be formedlocally within an anchor subband.

5. Resource Allocation

In NR, due to various reasons, time resource may not be contiguouslyavailable. In this sense, resource allocation may be done via dynamicscheduling, in both frequency and time domain, or only in frequencydomain or only in time domain. In other words, NR may support variousresource allocation. Accordingly, different granularity in terms offrequency or time resource may be allowed. For example, the size ofsubband used for frequency domain may be variable, or may beconfigurable by higher layer signaling, or implicitly adapted dependingon the bandwidth change or other reasons (restricted of bandwidth).

Furthermore, indication of time and frequency resource or time resourceonly or frequency resource only may be allowed. For example, when thereis only one UE per beam in most cases, it may be desirable that all thefrequency resources (only available) are used for single UE, which mayeliminate the necessity of resource allocation in frequency domain. Ifonly a few UEs are allocated, the all frequency resources may be dividedinto a few blocks (e.g. to the maximum number of UEs schedulable in onetime), and then how many blocks are assigned to each UE may beindicated. The number of frequency blocks in the entire system bandwidthfor a given UE (i.e. from UE-specific bandwidth perspective) may beindicated via higher layer signaling or dynamic signaling or viascheduling. Also, the assigned number of blocks may also be indicatedand the allocation may be done either bitmap manner or contiguousallocation manner. To realize this, the following approaches may beconsidered.

(1) Frequency blocks may be divided semi-statically, e.g. based on themaximum possible number of UEs, then resource allocation of each blockto UE may be indicated either via bitmap or start/end block indication.

(2) Frequency blocks may be divided into a few candidate numbers (e.g.1, 2, 4 or max number of UEs), which may be dynamically indicated viascheduling (e.g. first grant). The actual resource allocation size maybe different depending on the chosen candidate. For example, if 1 isselected, resource allocation in the next step in frequency domain maybe omitted.

(3) A few patterns may be defined and one pattern may be indicated. Forexample, patterns may include {(full bandwidth), (upper half bandwidth),(lower half bandwidth), (1/4th upper bandwidth, 2/4th upper bandwidth,3/4th bandwidth, 4/4th bandwidth), etc.}. In other words, combination ofthe number of frequency blocks and the allocation may be done. The setof patterns may be configured by higher layer, and the bandwidth sizemay also be configured to the UE.

Similarly, for time-domain resource, the following approaches may beconsidered.

(1) Unless otherwise configured (via semi-static signaling), a UE mayassume that all DL portions are available for DL data reception. In thiscase, a UE may be only configured with the number of slots in which onetransport block (TB) is spanning.

(2) A UE may assume that all resources may not be used for datatransmission. Only time resources indicated by DL scheduling or UL grantmay be valid for DL or UL. In this case, the indication mechanism may beas follows.

-   -   Bitmap to indicate the available OFDM symbols in a slot or        within multi-slots: Multi-slots size may be configured by higher        layer, or indicated by DCI.    -   Contiguous: For example, starting and duration of data        transmission may be indicated by DCI.    -   Time-domain resource block group (RBG) concept: OFDM symbols may        be grouped to a time-domain RBG, and individual resource mapping        per each time-domain RBG may be considered. One example of        time-domain RBG is to use mini-slot size. Mini-slot size may be        configured by higher layer. In each time-domain RBG, independent        bit may be used to indicate whether the time-domain RBG is used        for scheduling or not. To minimize dynamic size change of        time-domain RBG when dynamically slot and multi-slots are used        for scheduling, time-domain RBG size may be adapted depending on        the used number of slots. For example, if one slot is used,        time-domain RBG size may become 2 OFDM symbols. If 2 slots are        used, time-domain RBG size may become 4 OFDM symbols. If 4 slots        are used, time-domain RBG size may become 8 OFDM symbols.        Instead of bitmap of each time-domain RBG, similar to frequency        domain resource allocation, within each time-domain RBG, one or        more OFDM symbols may be selected for scheduling by adding a few        bits which are commonly applied to all time-domain RBGs.

If time-domain resource allocation is also used, this may be used forindicating various blank resources due to various reasons. One exampleis not to map data in CSI-RS resources which are destined to differentUEs from the scheduled UEs on the resource. Another example is to avoidlegacy LTE protected region such as cell-specific reference signal(CRS), PDCCH, etc.

(3) Time resource indication may be necessary in the following cases.

-   -   To mute around CSI-RS transmission for different beam(s) than        the beam used for data transmission (mostly TX beam)    -   To mute around SRS transmission for different beam(s) that the        beam assumed for data transmission (mostly RX beam)    -   To mute around forward compatible resources    -   To mute around inter-cell interference coordination (ICIC)        protected resources (e.g. LTE PDCCH, LTE CRS, protected region)    -   To schedule multi-slot scheduling or multi-mini-slot scheduling

(4) In terms of time resource, the duration or resource size may beconfigured (e.g. the maximum slot size)

(5) Time-domain resource may be grouped in a mini-slot or a set of OFDMsymbols and resource allocation may be applied per each group. In termsof resource allocation, contiguous or time resource group based approachmay be considered. Joint indication between frequency and time may alsobe considered.

Similar mechanisms may also be applied to common search space orgroup-specific search space and the configuration may be done via commonsignal such as SIB/MIB and/or group-cast.

As indication of both time and frequency domain may lead considerableoverhead, whether time and/or frequency resource allocation is used maybe indicated. Further, whether granularity of time/frequency resource isdone by adopting two-level or multi-level DCIs may also be indicated.The first level DCI, which may be shared among multiple UEs or done bycommon signal mentioned in the present invention, may indicate thegranularity of resource and/or resource allocation type. Depending onthe indication, the resource allocation size and/or interpretation maybe different. For UEs which may not be able to successfully decodecommon signal at least in some cases, a default setting may be used.

To indicate unavailable time/frequency resources, in addition to commonsignal for resource allocation type/granularity indication, invalidtime/frequency resource may also be indicated via common signal.Depending on signaling, the UE assumption on different channel may bedifferent. The followings are examples.

-   -   Common signal may indicate available time/frequency resources        for all channels. For example, DL/UL slot type or DL/UL size may        be commonly indicated.    -   Common signal may indicate available time/frequency resources        for all channels except for data channels. For example, the        available resources may be scheduled via dynamic scheduling        (UE-specifically), and common signal may indicate the available        resource for other channels such as CSI-RS, PUCCH, SRS, etc.        More generally, the signal may be applied to channels in which        resource may not be dynamically indicatable (e.g. periodically        configured channels, or channels with semi-static configuration        for the resources). For other channels, dynamic indication via        scheduling may be used.    -   Common signal may indicate minimum available time/frequency        resources and additional resources may be indicated to UE via        dynamic scheduling. When this approach is used, unless        additional indication is received, all channels may assume that        the indicated resource by common signal is the only available        resources. To handle the missing case, default minimum available        time/frequency resource may be preconfigured.    -   Common signal may indicate maximum available time/frequency        resource and additional restriction may be indicated to UE via        dynamic scheduling. When this approach is used, unless        additional indication is received, all channels may assume that        the indicated resource by common signal is the available        resources. To handle the missing case, default available        time/frequency resource may be preconfigured.

As common signal may be indicated per different UEs by grouping based ondifferent reasons (e.g. used numerology, usage scenario, service type,etc.), a UE may have to search more than one common signal(s). In termsof actual configuration/indication, instead of direct configuration oftime/frequency resource, index from pre-configured patterns may beconsidered. One example of pre-configured patterns may be as follows.

-   -   [00110110011011]: First, second, 4th symbols are not available        in each 7 OFDM symbols.    -   [001111111111111]: first and second symbols are not available        (e.g. multicast broadcast single-frequency network (MBSFN)).    -   [011111111111111]: only first symbol is not available.    -   [1111111111000000]: Downlink pilot time slot (DwPTS) region size        is 9 OFDM symbols for DL. Depending on GP size, uplink pilot        time slot (UpPTS) size may be 1, 2, 3, 4 (GP size becomes 4, 3,        2, 1).

6. Blank/Punctured Resource Indication

When eMBB/URLLC are multiplexed or some resources (e.g. invalid OFDMsymbols) are not available, indication mechanism of blank resource needsto be considered.

(1) Indication Mechanism

Common signal (CSS or UE-group search space) which contains informationon positions of indication signal may be indicated, and actualindication signal at the indicated position may also be indicated.Common signal may indicate the possible positions in which indicationsignal can be actually transmitted. In the indicated position, actualindication signal may be transmitted. For example, to support URLLC andeMBB data, possibly DL-centric slot type and DL-UL-symmetric slot typemay coexist. If the network has any URLLC UL data, the network mayswitch the slot type from DL-centric to DL-UL-symmetric slot type. Inthis case, the indicated position may be middle OFDM symbol or thestarting OFDM symbol of UpPTS of DL-UL-symmetric slot type. If theindication signal indicates the DL symbol there, the UE may assume thatDL-centric slot type is used.

Alternatively, positions of mini-slot may be indicated, and eachmini-slot may indicate DL or UL which are maintained until the nextindication position. To change the slot type, indicated positions mayinclude (1) first OFDM symbol of UpPTS in UL-centric slot type, (2)first OFDM symbol of UpPTS in DL-UL-symmetric slot type, and (3) firstOFDM symbol of UpPTS in DL-heavier slot type. DL-UL-symmetric slot typemay refer e.g. DDDDDDDGUUUUUU or DDDDDDGUUUUUUU or DDDGUUU. UL-centricslot type may refer e.g. DGUUUUU or DGUUUUUUUUUUUU. DL-heavier slot typemay refer e.g. DDDDGUU or DDDDDDDDDGUUUU (i.e. DL portion is larger thanUL portion). The indication may be implicit or explicit. When implicitindication is used, the position for sensing gap in which UEs or thenetwork may perform sensing for some other on-going high priority datatransmission may be used. High priority transmission may include thefollowings.

-   -   LTE transmission if LTE/NR coexist in LTE spectrum    -   DL transmission in DL intended resources    -   UL transmission in UL intended resources    -   URLLC traffic over eMBB    -   Any high priority transmission configured by the network

The indication may include both time and frequency information whereindication or sensing should be transmitted or occurred. Common signalmay indicate index from a set of preconfigured or configured patterns oftime/frequency resources. In addition to indicated position, indicationtype or indication reason may also be configured. For example,indication type or reason may be as follows.

-   -   Cross-link interference mitigation (sensing may be required):        Valid/invalid resource for UL in intended DL resource or        valid/invalid resource for DL in intended UL resource    -   URLLC puncture eMBB (indication may be signaled)

(2) UE Behavior on the Indicated Resource

-   -   The UE may detect indication signal. The indication signal may        be multiplexed with DL data. When the UE detects indication        signal, depending on the priority of data transmission/reception        of on-going, the UE may perform different things. For example,        eMBB UEs may assume that indication means invalid resource or        blank resource where the indication is applied, and may treat        the resource either as punctured or postponed. Indication may        also include validity and a UE may assume the indicated        resources are valid only if the signal/indication is detected.    -   The UE may perform sensing. For example, when a UE schedules UL,        on the indicated positions, the UE may sense whether there is        any on-going DL transmission or not. If sensing shows no DL        transmission, the UE may continue UL transmission. When sensing,        the UE may also sense URLLC UL transmission, and then can stop        UL transmission.    -   The UE behavior may be configured by the network. Depending on        UE type and usage scenarios, etc., the behavior may be        configured by the network. For example, the UE may assume        invalid resource or assume valid resource. Or, the UE may        puncture or rate matching or perform sensing or sensing target,        e.g., neighbor cell or other UEs or URLLC traffic, etc.

(3) Examples

-   -   For cross-link interference mitigation, in intended DL resource,        indication on invalid resource may be indicated for UL resource.        The indication signal may indicate either valid or invalid. A UE        transmitting in such resource may sense the configured/indicated        resource or detects the indication signal, and if the sensing        results shows IDLE or indication shows valid resource, UL        transmission may be continued. Otherwise, UL transmission may be        dropped, punctured, rate matched on the resources affected by        the indicated/sensing position. The affected resource may be        defined between two indication points (i.e. from the current        indication point to the next indication point).    -   For cross-link interference mitigation, in intended UL resource,        indication on invalid resource may be indicated for DL resource.        Different from the above description, if sensing is used,        sensing may be occurred by the network rather than UEs. When        sensing fails, the network may stop transmission. To avoid UE        buffer corruption, additional indication may also be considered        and actual sensing may be occurred before the indication. To        support this, blank resource for sensing of the network and        indicated position may be separately or jointly        configured/indicated by common signal. Or, a UE may blindly        search some signal/RS after indication point to detect whether        the transmission continues or not.    -   eMBB DL puncturing: if puncturing is possible due to URLLC DL or        URLLC UL on eMBB DL transmission, the indication may indicate        whether the puncturing has been occurred or not. In case of        URLLC UL and eMBB DL, indication may not be feasible to be        transmitted. Thus, UEs may assume that the resource are stolen        if indication is not detected.    -   eMBB UL puncturing: similar to DL, UL puncturing may also occur        to transmit URLLC DL or URLLC UL. In this case, explicit        indication on invalid resource indication may be used and UEs        may assume that the resources are invalid only if indication        signal(s) is detected. Otherwise, the UE may continue UL        transmission. In this case, it is more efficient to transmit UL        via mini-slot design in which gap or indication position may be        placed between mini-slots.

In terms of puncturing indication, as it is difficult to indicate priorto the transmission, post transmission indication may be considered, andcommon signal may be transmitted at the end of subframe/slot or in thebeginning of the next slot. When the common signal is used forpuncturing indication, common channel may be present only whenpuncturing has occurred. As the next slot/subframe may not have controlregion, the first available slot/subframe with control region maytransmit indication. As different UEs may have different informationabout available slot/subframe, the gap between punctured slot/subframeto the indicated subframe may be fixed (e.g. 1). When UE-specificindication of puncturing is used, resource allocation for retransmissionmay include puncturing indication. If such signaling is adopted, it isnot required that all UEs need to detect common signal. Only UEsscheduled with data may search the signal.

Common signal may also be used for stopping UL transmission. If a UEdetects common signal, the UE may halt any UL transmission in thecurrent or next few slots.

Or, simply a UE may cancel all the scheduled UL by dynamic DCI. If a UEis transmitting multi-slot UL transmission, the UE may drop the rest ofUL transmission once common signal is detected. If this signaling isused, the signaling transmission may be aperiodic and signaling may betransmitted only if puncturing is occurred. This may be associated withslot type and the puncturing may be indicated along with reservedresources. In case of puncturing, the indication type may indicatebackward or for previous slot/subframe. If puncturing indication viacommon signal is used, and code block (CB)-group based ACK/NACK is used,ACK/NACK for punctured CBs and CBs with low signal-to-interference andnoise ratio (SINR) (or low signal quality) may be separately indicatedso that redundancy versions (RVs) may be constructed differently. Commonsignal for puncturing case may also be used for inter-cell URLLCtransmission and a UE in a cell may overhear common signal from anothercell which can indicate puncturing indication. If those puncturedresource may have higher interference level and requires emptying thereceived resource due to higher interference level of URLLC, it may alsobe indicated to the network for recovery (or retransmission of systeminformation bits).

7. NR/LTE Coexistence

When NR is deployed in LTE spectrum either co-channel or in adjacentcarrier, to maximize resource utilization, blank resource may beindicated dynamically for NR. Blank resource may include resourcesnecessary for LTE operation. For example, the number of OFDM symbolsused for legacy PDCCH, whether the subframe is used for LTE transmissionor not, or subframe type, etc., may be indicated. Particularly when LTEand NR cells are collocated or connected via ideal backhaul, NR cell mayknow dynamic scheduling information. Otherwise, NR cell may listen onLTE control region (at least partially, e.g. read physical controlformat indicator channel (PCFICH), SIB, etc.) over air signaling betweenLTE and NR. Based on the information, NR cell may determine the startingposition of slot or control region.

The starting position or the set of valid or invalid resources may beindicated in the dedicated/reserved resource.

One example of dedicated/reserved resource for common signaltransmission is to utilize guard band of LTE band. For example, if NRband has smaller guard band via filtering, guard band may be utilizedfor some signaling transmission. Alternatively, time/frequency regionfor common signal transmission may be reserved for NR.

FIG. 10 shows an example of utilizing a guard band for common signalaccording to an embodiment of the present invention. Referring to FIG.10, NR transmission occurs with 30 kHz subcarrier spacing and itstransmission starts from 4th OFDM symbol.

The common signal may indicate at least one of a starting position fromwhich NR starts transmission (e.g. the number of legacy PDCCH region), aset of symbols usable for NR (e.g. blank OFDM symbols or available OFDMsymbols for NR transmission), or a pattern of available resource. Thepossible patterns may be as follows.

-   -   1 first OFDM symbol used for legacy PDCCH+2/4 port CRS TX normal        subframe (2 or 4 ports may be configured/indicated by higher        layer)    -   2 first OFDM symbol used for legacy PDCCH+2/4 port CRS TX normal        subframe (2 or 4 ports may be configured/indicated by higher        layer)    -   3 first OFDM symbol used for legacy PDCCH+2/4 port CRS TX normal        subframe (2 or 4 ports may be configured/indicated by higher        layer)    -   1 first OFDM symbol used for legacy PDCCH+2/4 port CRS TX MBSFN        subframe (2 or 4 ports may be configured/indicated by higher        layer)    -   2 first OFDM symbol used for legacy PDCCH+2/4 port CRS TX MBSFN        subframe (2 or 4 ports may be configured/indicated by higher        layer)

When a pattern is configured, the UE may assume that NR portion maystart at the available resource. In terms of handling of unavailableresource, rate matching or puncturing may be considered. Rate matchingmeans that control, RS or data are pushed to the next OFDM symbol if thecurrent symbol is not available or rate matched. Rate matching may beapplied only on control channel and associated RS. Data and demodulationreference signal (DM-RS) for PDSCH may be punctured in unavailableresources. It may be generally desirable to fix DM-RS position of dataand also control to the OFDM symbol(s) which are generally available toNR if the slot is available for NR. To minimize the misbehavior, adefault behavior may be as follows.

-   -   3 OFDM symbols may be used for legacy PDCCH (assuming 1.4 MHz        system bandwidth is not supported)    -   CRS (if present) may puncture NR transmission

If this is assumed, control region or slot may start at 4th OFDM symbol.When 30 kHz subcarrier spacing is used, the slot size of each slot maybe as 11 OFDM symbols (in total of 22 OFDM symbols within 1 ms,excluding 3 15 kHz OFDM symbols). Or, the first slot may be rate matchedor punctured only.

FIG. 11 shows an example of patterns for coexistence of LTE and NRaccording to an embodiment of the present invention. FIG. 11-(a) shows acase of equal slot size based on semi-static configuration. FIG. 11-(b)shows a case of equal slot size assuming all available resource. In thiscase, if common signal indicates that more resources are available, theavailable resource by the common/dynamic signaling may be used for dataportion. Even in this case, control region may be rather fixed, andremaining portions may be used for data. To improve reliability, DCI mayindicate a starting OFDM symbol of data earlier than the control region.In FIG. 11, DCI may indicate data transmission at −4 OFDM symbols. DM-RSposition(s) of data may rather be fixed based on the semi-staticconfiguration or fall back configuration. When available/unavailableresource sets are configured, one signal may contain information overmulti-slots rather than per slot basis. The resource may include bothtime and frequency.

This may be generally applied to cases where NR may exist stand-alone ina frequency spectrum as well, without loss of generality. Control regionmay be fixed as the first OFDM symbol in a slot.

8. eMBB/URLLC Multiplexing

Common signal may be used for eMBB/URLLC multiplexing and aidinformation for URLLC transmission. The followings are examples ofpossible indication information for eMBB/URLLC multiplexing/scheduling.

-   -   Slot prioritized for URLLC: eMBB UEs need to check indication        signal on puncturing. This may also be applicable to UL slot        type as well.    -   Slot prioritized for eMBB: URLLC data may not puncture the        transmitted data in the slot    -   Reserved resource for eMBB: Protected resources may be indicated        via common signal    -   Reserved channels/signals for eMBB: Protected channels/signals        in the slot which will not be punctured by URLLC may be        indicated via common signal.    -   Whether the slot can be used for contention based and/or        grant-free transmission: If the indication is present, the slot        may be usable for contention based or grant-free transmission.        Otherwise, the slot may not be used for contention and/or        grant-free transmission. With this mechanism, to adjust        contention resource dynamically, very large pool for contention        resource may be allocated, and then the resource may be        activated or deactivated per slot basis or in a multiple slots        basis.    -   If slot type is DL-centric or DL, contention resource may not be        available. If slot type is UL centric or UL, contention resource        may be available.    -   Multiple resource sets may be configured and activation or        deactivation of multiple resource sets may be indicated via        dynamic possibly common signaling.

9. Assistance on UE Blind Detection Reduction

One use case to utilize common signal is to indicate or assist UEcontrol channel blind detection reduction. As long-term scale blinddetection reduction may be done by either semi-static signaling ordynamic bandwidth adaptation, overall blind detection reduction may bedone per slot-basis. That is, blind detection reduction may occur in theslot or in the next slot in which common signal has beentransmitted/received. For the best quality, common signal for blinddetection reduction assistance may be transmitted in the previous slot.The transmission point of common signal or gap between common signal anda slot where common signal is applied may be configured (the gap may be0, 1 . . . etc.). The information about control region size may beinserted with CRC on the common channel or scrambling may be useddifferently depending on the size of control region size. In otherwords, the control region size in time domain may be transmittedopportunistically if common signal is transmitted, and the informationmay be embedded as CRC or scrambling, to minimize payload size.

If common signal is for multiple carriers, the control region size isonly for the carrier where the signal is transmitted. In other words,other carriers without common signal transmission may not transmitcontrol region size dynamically. Furthermore, saving of blind detectionswith common signal may be configured or applied only when a UE expectsthat CCEs are mapped in frequency first manner. In other words, PDCCHsare rather confined within OFDM symbols. Alternatively, if controlregion size is fixed and some resources are fixed regardless of commonsignal to indicate control region size, time-first mapping may be usedwithin the fixed resource, and frequency first mapping may be usedwithin flexible resource. If scrambling or CRC is used to delivercontrol region size, if common control is not configured or nottransmitted, CRC or scrambling may be done in some other cell-common RStransmissions such as CSI-RS, tracking RS, measurement RS, etc. Ifcommon signal is transmitted from the previous slot, blind detectionreduction in terms of numbers, percentages, etc., may also beconsidered. Another approach of blind detection reduction is to indicatea set of UE groups which are scheduled in the current or next slotinstead of control region size. This may be done via M bits bitmap,where M may be the number of UE groups. A UE based on its RNTI or UE-IDmay determine its group, and does not perform blind decoding if thegroup does not have scheduling indication.

For another possible blind detection reduction, at leastcross-subframe/slot scheduling may be used, the starting of data may notbe smaller than end of control region. For example, if a UE is scheduledwith data starting at 3rd OFDM symbol in n+4, a UE, au assume thatcontrol region size is 2 symbols in slot/subframe n+4, regardless ofconfigurations. However, control resource sets may not cover the entireUE bandwidth where the UE monitors control and/or data. In that case,PDSCH starting may be indicated as earlier than the end of controlregion. In this case, data may be rate matched on the configured controlresource sets. Whether a UE can assume that control region size issmaller than the starting of data transmission or not forcross-subframe/slot scheduling may be configured/informed by higherlayer. This may not be true for the same-slot/subframe scheduling, ascontrol region size of USS can be longer than the starting of datatransmission. If there is indication whether a UE can assume TDM betweencontrol region and data region via explicit or implicit indication, itmay also be applied to same-slot/subframe scheduling.

One useful case of blind detection reduction by indicating controlregion size is the case that cross-carrier scheduling of common signalis achieved by a carrier with larger subcarrier spacing to anothercarrier with smaller subcarrier spacing. In this case, the informationmay be applied to the same slot where cross-carrier scheduling applied,or to the next slot after cross-carrier scheduling is received. If thiscase is supported, control region size for a carrier may be included inthe content of common signal, and common signal may be transmitted viacross-carrier scheduling. Control region size may also be indicated as apart of slot type indication, and no additional information may benecessary if UL-centric or UL or reserved slot type is indicated, ascontrol region in such cases are clear. Additional control region sizemay be indicated only if DL centric or DL slot is indicated where thesize of control region may be additionally transmitted. Jointtransmission of slot type and control region size may also be consideredas follows as examples.

-   -   [1 symbol DL-control, DL-centric, 1 symbol UL-control], [1        symbol DL-control, DL-centric, 2 symbol UL-control]    -   [2 symbol DL-control, DL-centric, 1 symbol UL-control], [2        symbol DL-control, DL-centric, 2 symbol UL-control]    -   [3 symbol DL-control, DL-centric, 1 symbol UL-control], [3        symbol DL-control, DL-centric, 2 symbol UL-control]    -   [1 symbol DL-control, UL-centric, 1 symbol UL-control], [1        symbol DL-control, UL-centric, 2 symbol UL-control]    -   [2 symbol DL-control, UL-centric, 1 symbol UL-control], [2        symbol DL-control, UL-centric, 2 symbol UL-control]    -   [3 symbol DL-control, UL-centric, 1 symbol UL-control], [3        symbol DL-control, UL-centric, 2 symbol UL-control]

Other patterns may also be considered. The above patterns may bepotentially subsets of possible configurations. The slot type ofmultiple slots excluding fixed DL or UL or reserved slots or fixed DL/ULslots, if periodically common signal is transmitted, may be transmitted.

If control region size is indicated via common signal, it needs to beclarified whether the signaling is applied to all UEs' control region orsome UEs only. The UEs receiving the corresponding group common RNTI mayassume that the same size may be applied to all configured controlresource sets. If different size are applied or configured to eachcontrol resource set, common signal may indicate unmapped control regionin OFDM symbols, instead of control region size. For example, if controlregion size is configured as 3 OFDM symbols semi-statically, and commonsignal indicates that two symbols are unmapped for control region, a UEmay assume that 1 OFDM symbol is used for control region. By this way,the same reduction may be applied to all configured resource sets whichcan lead still different control resource set sizes in time domain.Alternatively, different group common RNTI may be configured to each ora subset of resource sets as well, and different indication may beexpected.

In millimeter wave (mmWave) environment, it is challenging to transmitcommon signal. If common signal is adopted, whether there will bescheduling to the same beam direction in the next slot or not may beindicated. For example, if the network has transmitted beam 1, 3, 5 inslot n, for each beam 1, 3, and 5, the network may indicate whetherthere will be control scheduling to beam 1, 3, and 5 or notrespectively. If scheduling is not indicated for the next slot, a UE mayskip decoding on the next slot if the UE is configured with the beam(s).Also to minimize blind decoding on resources used for different beamsthan the configured beams from a UE perspective, a set of candidate OFDMsymbols may be determined based on a function or a rule. For example, ifa UE supports total of N beams, and maximum K beams can be transmittedper slot, and a UE expects about P times of monitoring occasions duringN/K slots, a UE may monitor control region in slots N*P/K*i+UE-ID orRNTI % N*P/K, where i=0, 1, 2 . . . P−1. The idea is to distributemonitoring occasions evenly for UEs. Different function can beconsidered.

Another approach is to map CCEs across multiple slots. The number ofslots may be configured by the network dynamically or semi-staticallyand a UE may access different OFDM symbols for searching candidatesbased on hashing function. In this case, to allow multiplexing of UEswith the same beam to the same OFDM symbols, the same hashing functionmay be used among UEs sharing the same beam ID. In other words, hashingfunction may be based on beam ID or the associated CSI-RS resource indexwhere a UE expects to receive the data. To minimize the collision amongUEs with the same beam ID, secondary hashing may be used after applyinghashing based on beam ID. Alternatively, hashing function based on beamID may be performed at OFDM symbol level, and if the network configuresK control symbols in each slot over M slots, total of K*M symbols may beavailable for hashing. The number of candidate symbols, e.g. P, may beselected based on hashing function and the configured offset. Or, P OFDMsymbols may be randomly selected based on hashing/randomizationfunctions. Secondary hashing may be performed in the selected symbols.

FIG. 12 shows a method for handling priority of a common control signalby a UE according to an embodiment of the present invention. The presentinvention described above may be applied to this embodiment.

In step S100, the UE receives the common control signal from a networkvia a GCCC. The common control signal is for all UEs or a group of UEsin a cell. In step S110, the UE handles the priority of the commoncontrol signal compared to other signals.

The priority of the common control signal may be higher than asemi-static UE-specifically configured configuration. The priority ofthe common control signal may be lower than a cell-commonly orgroup-commonly configured configuration. The priority of the commoncontrol signal may be lower than a dynamic UE-specifically configuredconfiguration.

The priority of the common control signal may be higher than asemi-static configuration when the common control signal indicates aflexible resource. The flexible resource may be determined by asemi-static DL/UL configuration. The flexible resource may be determinedby a resource or RS type of the semi-static configuration. The flexibleresource may be determined by a configuration method.

The priority of the common control signal may be lower than asemi-static configuration when the common control signal indicates afixed DL resource or a UL resource.

The common control signal may be received in a subset of candidates orin a first OFDM symbol of a control region or in a frequency regionamong control resource sets.

The common control signal may indicate at least one of whether a type ofa current subframe is UL-centric or DL-centric, whether a type of a nextsubframe type is UL-centric or DL-centric, whether the current subframeis scheduled with single-level DCI or multi-level DCI, whether the nextsubframe is scheduled with single-level DCI or multi-level DCI, a sizeof common or group-specific shared control resource set, or anindication of actual DL resource, UL resource and/or reserved resource.

The common control signal may be received via either self-carrierscheduling or a cross-carrier scheduling.

An exact length of a long PUCCH format may be indicated from thenetwork. The UE may receive a DL data from the network, and transmit aUL control signal to the network via the long PUCCH format.

FIG. 13 shows a wireless communication system to implement an embodimentof the present invention.

A network node 800 includes a processor 810, a memory 820 and atransceiver 830. The processor 810 may be configured to implementproposed functions, procedures and/or methods described in thisdescription. Layers of the radio interface protocol may be implementedin the processor 810. The memory 820 is operatively coupled with theprocessor 810 and stores a variety of information to operate theprocessor 810. The transceiver 830 is operatively coupled with theprocessor 810, and transmits and/or receives a radio signal.

A UE 900 includes a processor 910, a memory 920 and a transceiver 930.The processor 910 may be configured to implement proposed functions,procedures and/or methods described in this description. Layers of theradio interface protocol may be implemented in the processor 910. Thememory 920 is operatively coupled with the processor 910 and stores avariety of information to operate the processor 910. The transceiver 930is operatively coupled with the processor 910, and transmits and/orreceives a radio signal.

The processors 810, 910 may include application-specific integratedcircuit (ASIC), other chipset, logic circuit and/or data processingdevice. The memories 820, 920 may include read-only memory (ROM), randomaccess memory (RAM), flash memory, memory card, storage medium and/orother storage device. The transceivers 830, 930 may include basebandcircuitry to process radio frequency signals. When the embodiments areimplemented in software, the techniques described herein can beimplemented with modules (e.g., procedures, functions, and so on) thatperform the functions described herein. The modules can be stored inmemories 820, 920 and executed by processors 810, 910. The memories 820,920 can be implemented within the processors 810, 910 or external to theprocessors 810, 910 in which case those can be communicatively coupledto the processors 810, 910 via various means as is known in the art.

In view of the exemplary systems described herein, methodologies thatmay be implemented in accordance with the disclosed subject matter havebeen described with reference to several flow diagrams. While forpurposed of simplicity, the methodologies are shown and described as aseries of steps or blocks, it is to be understood and appreciated thatthe claimed subject matter is not limited by the order of the steps orblocks, as some steps may occur in different orders or concurrently withother steps from what is depicted and described herein. Moreover, oneskilled in the art would understand that the steps illustrated in theflow diagram are not exclusive and other steps may be included or one ormore of the steps in the example flow diagram may be deleted withoutaffecting the scope of the present disclosure.

1. A method performed by a user equipment (UE) in a wirelesscommunication system, the method comprising: receiving a group commoncontrol signal from a network via a group common control channel (GCCC),wherein the group common control signal is scheduled to a group of UEswith a radio network temporary identity (RNTI) specific to the groupcommon control channel; receiving a signal other than then group commoncontrol signal from the network; and handling a priority of the groupcommon control signal compared to a priority of the signal.
 2. Themethod of claim 1, wherein the priority of the group common controlsignal is higher than the priority of the signal when the signal is asemi-static UE-specifically configured configuration.
 3. The method ofclaim 1, wherein the priority of the group common control signal islower than the priority of the signal when the signal is a semi-staticcell-commonly configured configuration.
 4. The method of claim 1,wherein the priority of the group common control signal is lower thanthe priority of the signal when the signal is a dynamic UE-specificallyindicated configuration via scheduling. 5-9. (canceled)
 10. The methodof claim 1, wherein the group common control signal is received in asubset of candidates or in a first orthogonal frequency divisionmultiplexing (OFDM) symbol of a control region or in a frequency regionamong control resource sets.
 11. The method of claim 1, wherein thegroup common control signal indicates at least one of whether a type ofa current subframe is UL-centric or DL-centric, whether a type of a nextsubframe type is UL-centric or DL-centric, whether the current subframeis scheduled with single-level downlink control information (DCI) ormulti-level DCI, whether the next subframe is scheduled withsingle-level DCI or multi-level DCI, a size of common or group-specificshared control resource set, or an indication of actual DL resource, ULresource and/or reserved resource.
 12. The method of claim 1, whereinthe group common control signal is received via either self-carrierscheduling or a cross-carrier scheduling.
 13. The method of claim 1,wherein an exact length of a long physical uplink control channel(PUCCH) format is indicated from the network.
 14. (canceled)
 15. A userequipment (UE) in a wireless communication system, the UE comprising: amemory; a transceiver; and a processor, operably coupled to the memoryand the transceiver, that: controls the transceiver to receive a groupcommon control signal from a network via a group common control channel(GCCC), wherein the group common control signal is scheduled to a groupof UEs with a radio network temporary identity (RNTI) specific to thegroup common control channel, controls the transceiver to receive asignal other than then group common control signal from the network, andhandles a priority of the group common control signal compared to apriority of the signal.
 16. The method of claim 2, wherein thesemi-static UE-specifically configured configuration is a configurationof a sounding reference signal (SRS) transmission.
 17. The method ofclaim 2, wherein the semi-static UE-specifically configuredconfiguration is a configuration of a channel state informationreference signal (CSI-RS) transmission.
 18. The method of claim 3,wherein the semi-static cell-commonly configured configuration is aconfiguration of at least one of a system information block (SIB) or aphysical broadcast channel (PBCH).
 19. The method of claim 1, whereinthe group common control signal indicates a first resource type, andwherein the signal indicates a second resource type different from thefirst resource type.
 20. The method of claim 19, wherein the groupcommon control signal overrides the signal when the second resource typeindicates a flexible resource.
 21. The method of claim 19, wherein thegroup common control signal does not override the signal when the secondresource type indicates a fixed downlink (DL) resource or a fixed uplink(UL) resource.